def print_precision_recall(classifier, test_dict):
refsets = defaultdict(set)
testsets = defaultdict(set)
for i, (feats, label) in enumerate(test_dict):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
print 'pos precision:', precision(refsets['positive'], testsets['positive'])
print 'pos recall:', recall(refsets['positive'], testsets['positive'])
print 'pos F-measure:', f_measure(refsets['positive'], testsets['positive'])
print 'neg precision:', precision(refsets['negative'], testsets['negative'])
print 'neg recall:', recall(refsets['negative'], testsets['negative'])
print 'neg F-measure:', f_measure(refsets['negative'], testsets['negative'])
def evaluate_features(feature_select):
posFeatures = []
negFeatures = []
#http://stackoverflow.com/questions/367155/splitting-a-string-into-words-and-punctuation
#breaks up the sentences into lists of individual words (as selected by the input mechanism) and appends 'pos' or 'neg' after each list
#could be replaced by word_tokenize
with open(RT_POLARITY_POS_FILE, 'r') as posSentences:
for i in posSentences:
posWordsMod = []
posWordsMod = get_words(i)
#print("\n Printing poswordsMod: ")
#print(posWordsMod)
#feature_select(posWords) is a dictionary
posWordsMod = [feature_select(posWordsMod), 'pos']
posFeatures.append(posWordsMod)
with open(RT_POLARITY_NEG_FILE, 'r') as negSentences:
for i in negSentences:
negWordsMod = []
negWordsMod = get_words(i)
negWordsMod = [feature_select(negWordsMod), 'neg']
negFeatures.append(negWordsMod)
# posFeatures looks like [....[{'word': True}, 'pos'] , ...]
#selects 3/4 of the features to be used for training and 1/4 to be used for testing
posCutoff = int(math.floor(len(posFeatures) * 3 / 4))
negCutoff = int(math.floor(len(negFeatures) * 3 / 4))
trainFeatures = posFeatures[:posCutoff] + negFeatures[:negCutoff]
testFeatures = posFeatures[posCutoff:] + negFeatures[negCutoff:]
#trains a Naive Bayes Classifier
classifier = NaiveBayesClassifier.train(trainFeatures)
#user_input = raw_input("Enter text for analysis")
#initiates referenceSets and testSets
referenceSets = collections.defaultdict(set)
testSets = collections.defaultdict(set)
#puts correctly labeled sentences in referenceSets and the predictively labeled version in testsets
for i, (features, label) in enumerate(testFeatures):
referenceSets[label].add(i)
predicted = classifier.classify(features)
testSets[predicted].add(i)
#prints metrics to show how well the feature selection did
print 'train on %d instances, test on %d instances' % (len(trainFeatures),
len(testFeatures))
print 'accuracy:', nltk.classify.util.accuracy(classifier, testFeatures)
print 'pos precision:', precision(referenceSets['pos'], testSets['pos'])
print 'pos recall:', recall(referenceSets['pos'], testSets['pos'])
print 'neg precision:', precision(referenceSets['neg'], testSets['neg'])
print 'neg recall:', recall(referenceSets['neg'], testSets['neg'])
classifier.show_most_informative_features(10)
test_data = raw_input("Enter text for analysis: ")
test_data = get_words(test_data)
test_data = feature_select(test_data)
print 'feature selection', test_data
print 'prediction: ', classifier.classify(test_data)
def get_precision(trainfeats, testfeats, my_classifier, dataset,
classifier_name):
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(testfeats):
refsets[label].add(i)
observed = my_classifier.classify(feats)
testsets[observed].add(i)
# precision and recall
accuracy = nltk.classify.util.accuracy(my_classifier, testfeats) * 100
pos_prec = precision(refsets['pos'], testsets['pos']) * 100
pos_rec = recall(refsets['pos'], testsets['pos']) * 100
neg_prec = precision(refsets['neg'], testsets['neg']) * 100
neg_rec = recall(refsets['neg'], testsets['neg']) * 100
# round
accuracy = round(accuracy, 1)
pos_prec = round(pos_prec, 1)
pos_rec = round(pos_rec, 1)
neg_prec = round(neg_prec, 1)
neg_rec = round(neg_rec, 1)
output_text = classifier_name + ", " + str(accuracy) + ", " + str(
pos_prec) + ", " + str(neg_prec) + ", " + str(pos_rec) + ", " + str(
neg_rec) + "\n"
def get_performance(clf_sel, train_features, test_features):
ref_set = collections.defaultdict(set)
test_set = collections.defaultdict(set)
classification_error = False
clf = SklearnClassifier(clf_sel)
try:
classifier = clf.train(train_features)
except:
classification_error = True
# print (str(clf_sel.__class__),'NA')
if str(clf_sel.__class__) == "<class 'sklearn.naive_bayes.MultinomialNB'>":
pickle_cls(classifier, 'MultinomialNB')
# print(str(clf_sel), 'accuracy:'(nltk.classify.accuracy(classifier, test_features)) * 100)
if not classification_error:
clf_acc = nltk.classify.accuracy(classifier, test_features)
for i, (features, label) in enumerate(test_features):
ref_set[label].add(i)
predicted = classifier.classify(features)
test_set[predicted].add(i)
pos_precision = precision(ref_set['pos'], test_set['pos'])
pos_recall = recall(ref_set['pos'], test_set['pos'])
neg_precision = precision(ref_set['neg'], test_set['neg'])
neg_recall = recall(ref_set['neg'], test_set['neg'])
print(
"{0},{1},{2},{3},{4},{5}".format(clf_sel.__class__, clf_acc, pos_precision, pos_recall, neg_precision,
neg_recall))
def review_evaluate_classifier(featx):
negids = movie_reviews.fileids('neg')
posids = movie_reviews.fileids('pos')
print(movie_reviews.words(fileids=[negids[0]]))
negfeats = [(featx(movie_reviews.words(fileids=[f])), 'neg') for f in negids]
posfeats = [(featx(movie_reviews.words(fileids=[f])), 'pos') for f in posids]
negcutoff = int(len(negfeats) * 3 / 4)
poscutoff = int(len(posfeats) * 3 / 4)
trainfeats = negfeats[:negcutoff] + posfeats[:poscutoff]
testfeats = negfeats[negcutoff:] + posfeats[poscutoff:]
classifier = NaiveBayesClassifier.train(trainfeats)
pickle.dump(classifier, open('/Users/SilverNarcissus/PycharmProjects/wordAnalysis/reviews_classifier.pkl', 'wb'))
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(testfeats):
refsets[label].add(i)
# 分类化过程
observed = classifier.classify(feats)
testsets[observed].add(i)
print('accuracy:', nltk.classify.util.accuracy(classifier, testfeats))
print('pos precision:', precision(refsets['pos'], testsets['pos']))
print('pos recall:', recall(refsets['pos'], testsets['pos']))
print('neg precision:', precision(refsets['neg'], testsets['neg']))
print('neg recall:', recall(refsets['neg'], testsets['neg']))
classifier.show_most_informative_features()
def evaluate_classifier(featx):
negids = movie_reviews.fileids('neg')
posids = movie_reviews.fileids('pos')
# print(movie_reviews.words(fileids=[negids[0]]))
# exit()
negfeats = [(featx(movie_reviews.words(fileids=[f])), 'neg') for f in negids]
posfeats = [(featx(movie_reviews.words(fileids=[f])), 'pos') for f in posids]
negcutoff = int(len(negfeats) * 3 / 4)
poscutoff = int(len(posfeats) * 3 / 4)
trainfeats = negfeats[:negcutoff] + posfeats[:poscutoff]
testfeats = negfeats[negcutoff:] + posfeats[poscutoff:]
print('train on %d instances, test on %d instances' % (len(trainfeats), len(testfeats)))
classifier = NaiveBayesClassifier.train(trainfeats)
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(testfeats):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
print('accuracy:', nltk.classify.util.accuracy(classifier, testfeats))
print('pos precision:', precision(refsets['pos'], testsets['pos']))
print('pos recall:', recall(refsets['pos'], testsets['pos']))
print('pos F-measure:', f_measure(refsets['pos'], testsets['pos']))
print('neg precision:', precision(refsets['neg'], testsets['neg']))
print('neg recall:', recall(refsets['neg'], testsets['neg']))
print('neg F-measure:', f_measure(refsets['neg'], testsets['neg']))
classifier.show_most_informative_features()
def pros_cons_evaluate_classifier(featx):
print(pros_cons.sents(categories='Pros')[1])
posfeats = [(featx(f), 'pros') for f in pros_cons.sents(categories='Pros')]
negfeats = [(featx(f), 'cons') for f in pros_cons.sents(categories='Cons')]
negcutoff = int(len(negfeats) * 3 / 4)
poscutoff = int(len(posfeats) * 3 / 4)
trainfeats = negfeats[:negcutoff] + posfeats[:poscutoff]
testfeats = negfeats[negcutoff:] + posfeats[poscutoff:]
# pipeline = Pipeline([('tfidf', TfidfTransformer()),
# ('chi2', SelectKBest(chi2, k=1000)),
# ('nb', MultinomialNB())])
# classifier = SklearnClassifier(pipeline)
classifier = NaiveBayesClassifier.train(trainfeats)
# pickle.dump(classifier, open('/Users/SilverNarcissus/PycharmProjects/wordAnalysis/pros_cons_classifier.pkl', 'wb'))
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(testfeats):
refsets[label].add(i)
# 分类化过程
observed = classifier.classify(feats)
testsets[observed].add(i)
print('accuracy:', nltk.classify.util.accuracy(classifier, testfeats))
print('pos precision:', precision(refsets['pros'], testsets['pros']))
print('pos recall:', recall(refsets['pros'], testsets['pros']))
print('neg precision:', precision(refsets['cons'], testsets['cons']))
print('neg recall:', recall(refsets['cons'], testsets['cons']))
classifier.show_most_informative_features()
def main():
negfeats = []
posfeats = []
for i, f in enumerate(reviews[0]):
print(f)
if reviews[1][i] == 0:
negfeats.append((word_feats(f.split()), "neg"))
else:
posfeats.append((word_feats(f.split()), "pos"))
testNegfeats = []
testPosfeats = []
for i, f in enumerate(test[0]):
if test[1][i] == 0:
testNegfeats.append((word_feats(f.split()), "neg"))
else:
testPosfeats.append((word_feats(f.split()), "pos"))
trainfeats = negfeats + posfeats
testfeats = testNegfeats + testPosfeats
print('train on %d instances, test on %d instances - Maximum Entropy' %
(len(trainfeats), len(testfeats)))
classifier = MaxentClassifier.train(trainfeats,
'GIS',
trace=0,
encoding=None,
labels=None,
gaussian_prior_sigma=0,
max_iter=1)
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(testfeats):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
accuracy = nltk.classify.util.accuracy(classifier, testfeats)
pos_precision = precision(refsets['pos'], testsets['pos'])
pos_recall = recall(refsets['pos'], testsets['pos'])
pos_fmeasure = f_measure(refsets['pos'], testsets['pos'])
neg_precision = precision(refsets['neg'], testsets['neg'])
neg_recall = recall(refsets['neg'], testsets['neg'])
neg_fmeasure = f_measure(refsets['neg'], testsets['neg'])
print(pos_recall)
print(neg_recall)
print()
print('')
print('---------------------------------------')
print(' Maximum Entropy ')
print('---------------------------------------')
print('accuracy:', accuracy)
print('precision', (pos_precision + neg_precision) / 2)
print('recall', (pos_recall + neg_recall) / 2)
print('f-measure', (pos_fmeasure + neg_fmeasure) / 2)
def assess_classifier(classifier, test_data, text, max_ent_help=False):
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
numDataSets = len(test_data)
onDataSet = 0
# TN = 0
# TP = 0
# FN = 0
# FP = 0
# enumerate through the test data and classify them
for i, (feats, label) in enumerate(test_data):
refsets[label].add(i)
if max_ent_help:
if maxEntClf.classify(feats):
observed = classifier.classify(feats)
else:
observed = False
else:
observed = classifier.classify(feats)
testsets[observed].add(i)
onDataSet += 1
# if label == observed:
# if observed:
# TP += 1
# else:
# TN += 1
# else:
# if observed:
# FP += 1
# else:
# FN += 1
# printPercentage(onDataSet/numDataSets * 100, "Extracting Features: ")
# precision = TP/(TP+FP)
# recall = TP/(TP+FN)
# f1Score = 2*((precision*recall)/(precision + recall))
# calculate the precisionl, recall, f-measure
laugh_precision = precision(refsets[True], testsets[True])
laugh_recall = recall(refsets[True], testsets[True])
laugh_f1 = f_measure(refsets[True], testsets[True])
non_laugh_precision = precision(refsets[False], testsets[False])
non_laugh_recall = recall(refsets[False], testsets[False])
non_laugh_f1 = f_measure(refsets[False], testsets[False])
acc = nltk.classify.accuracy(classifier, test_data)
return [text, acc, laugh_precision, laugh_recall, laugh_f1, non_laugh_precision, non_laugh_recall, non_laugh_f1]
def GetEvaluacion(self):
'''
Devuelve las medidas de precision, recall, y matriz de confusion del clasificador.
Para esto usamos las funciones precision, recall y confusion matrix de nltk y el conjunto
de testeo.
Retorna una tupla (positivos, negativos, matriz) donde positivos y negativos es otra tupla con los valores (precision, recall)
Precision: Fraccion de las instancias que se clasificaron correctamente / Fraccion de las instancias que se clasificaron en la clase:
TP / (TP + FP)
Cuanto mayor es esto, menor es la cantidad de falsos positivos, es decir, esto me da el porcentaje de los elementos que
fueron clasificados correctamente en esta clase.
Recall: Fraccion de las instancias que se clasificaron correctamente / Fraccion de las instancias que realmente estaban en la clase:
TP / (TP + FN)
Cuanto mayor es esto, menor es la cantidad de falsos negativos, es decir, del total de elementos que realmente existen
en la clase, cuantos clasifique.
Tanto precision y recall son para las clases y no en general (o sea, hay un valor de precision/recall para la clase de comentarios
positivos y otros para la clase de comentarios negativos)
Vale la pena leer de aca: http://streamhacker.com/2010/05/17/text-classification-sentiment-analysis-precision-recall/
'''
clasificador = self.GetClasificador()
corpus = self.DatosTesteo
#Las funciones de NLTK usan sets.
#Construyo sets de referencia y testeo para positivos y negativos.
refSet = {CLASE_POSITIVO:set(), CLASE_NEGATIVO:set()} #Tiene los valores reales
testSet = {CLASE_POSITIVO:set(), CLASE_NEGATIVO:set()} #Tiene los valores luego de clasificar.
#Valores para la matriz de conf.
refList = []
testList = []
#Tengo que construir conjuntos de referencia y testeo a partir de los de testeo, para poder usar las funciones de nltk
for i, c in enumerate(corpus):
refSet[c[1]].add(i) #Lo agrega en los positivos o negativos segun su clase.
clasificado = clasificador.classify(c[0])
testSet[clasificado].add(i)
refList.append(c[1])
testList.append(clasificado)
positivos = ( precision(refSet[CLASE_POSITIVO], testSet[CLASE_POSITIVO]), recall(refSet[CLASE_POSITIVO], testSet[CLASE_POSITIVO]) )
negativos = ( precision(refSet[CLASE_NEGATIVO], testSet[CLASE_NEGATIVO]), recall(refSet[CLASE_NEGATIVO], testSet[CLASE_NEGATIVO]) )
return (positivos, negativos, ConfusionMatrix(refList, testList))
def multi_metrics(multi_classifier, test_feats):
mds = []
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feat, labels) in enumerate(test_feats):
for label in labels:
refsets[label].add(i)
guessed = multi_classifier.classify(feat)
for label in guessed:
testsets[label].add(i)
mds.append(metrics.masi_distance(set(labels), guessed))
avg_md = sum(mds) / float(len(mds))
precisions = {}
recalls = {}
for label in multi_classifier.labels():
precisions[label] = metrics.precision(refsets[label], testsets[label])
recalls[label] = metrics.recall(refsets[label], testsets[label])
return precisions, recalls, avg_md
def train_and_score(classifier, train, test):
try:
if classifier.__name__ == 'MaxentClassifier':
clf = classifier.train(train, algorithm='MEGAM')
elif classifier.__name__ == 'DecisionTreeClassifier':
clf = classifier.train(train,
binary=True,
entropy_cutoff=0.8,
depth_cutoff=5,
support_cutoff=3)
else:
clf = classifier.train(train)
except AttributeError:
clf = classifier.train(train)
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(test):
refsets[label].add(i)
observed = clf.classify(feats)
testsets[observed].add(i)
measures = []
for key in refsets.keys():
measures.append([
precision(refsets[key], testsets[key]),
recall(refsets[key], testsets[key]),
f_measure(refsets[key], testsets[key])
])
return measures
def precision_recall(classifier, testfeats):
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
ref = []
pred = []
for i, (feats, label) in enumerate(testfeats):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
# Create 2 lists for Confusion Matrix
pred.append(observed)
ref.append(label)
cm = ConfusionMatrix(ref, pred)
print(cm)
precisions = {}
recalls = {}
for label in classifier.labels():
precisions[label] = precision(refsets[label], testsets[label])
recalls[label] = recall(refsets[label], testsets[label])
return precisions, recalls
def benchmarking(self,
classifier,
_test_set,
all_f_measure=[],
all_precision=[],
all_recall=[]):
from nltk import classify
accuracy = classify.accuracy(classifier, _test_set)
print("accuracy:", accuracy)
from nltk.metrics import precision
from nltk.metrics import recall
from nltk.metrics import f_measure
import collections
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(_test_set):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
prec = precision(refsets['class'], testsets['class'])
rec = recall(refsets['class'], testsets['class'])
f1 = f_measure(refsets['class'], testsets['class'])
print('precision:', prec)
print('recall:', rec)
print('F-measure:', f1)
all_f_measure.append(f1)
all_precision.append(prec)
all_recall.append(rec)
print('========Show top 10 most informative features========')
classifier.show_most_informative_features(10)
def precision_and_recall(classifier, testfeats):
#Finds precision and recall on that big booty classifier.
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
#Feats is the dictionary of words
#label is the label, pos or neg
for i, (feats, label) in enumerate(testfeats):
#a mapping of which entries are pos and negative
#ex refsets[pos] = {1,2,3,4,6,7,11,78}
refsets[label].add(i)
#Classifies something as pos or neg given its feats
observed = classifier.classify(feats)
#a mapping of entries and their classifications
#ex testsets[pos] = {1,2,3,4,5,8,11}
testsets[observed].add(i)
prec = {}
rec = {}
for label in classifier.labels():
prec[label] = precision(refsets[label], testsets[label])
rec[label] = recall(refsets[label], testsets[label])
return prec, rec
def main():
results = {'Topic': [], 'Precision': [], 'Recall': [], 'F-measure': []}
print('\nPreparing data...')
(train_set, test_set) = get_train_test_sets('data/content')
print('\nNB classifier training...')
classifier = NaiveBayesClassifier.train(train_set)
print('NB classifier is trained with {}% accuracy'.format(
round(accuracy(classifier, test_set) * 100, 1)))
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(test_set):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
for topic in topics:
results['Topic'].append(topic)
results['Precision'].append(
round(precision(refsets[topic], testsets[topic]) * 100, 1))
results['Recall'].append(
round(recall(refsets[topic], testsets[topic]) * 100, 1))
results['F-measure'].append(
round(f_measure(refsets[topic], testsets[topic]) * 100, 1))
del classifier, train_set, test_set, refsets, testsets
gc.collect()
print(results)
def multi_metrics(multi_classifier, test_feats):
mds = []
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feat, labels) in enumerate(test_feats):
for label in labels:
refsets[label].add(i)
guessed = multi_classifier.classify(feat)
for label in guessed:
testsets[label].add(i)
mds.append(metrics.masi_distance(set(labels), guessed))
avg_md = sum(mds) / float(len(mds))
precisions = {}
recalls = {}
for label in multi_classifier.labels():
precisions[label] = metrics.precision(refsets[label], testsets[label])
recalls[label] = metrics.recall(refsets[label], testsets[label])
return precisions, recalls, avg_md
def benchmarking(self, classifier,_test_set,all_f_measure=[],all_precision=[],all_recall=[]):
from nltk import classify
accuracy = classify.accuracy(classifier, _test_set)
print("accuracy:",accuracy)
from nltk.metrics import precision
from nltk.metrics import recall
from nltk.metrics import f_measure
import collections
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(_test_set):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
prec=precision(refsets['class'], testsets['class'])
rec=recall(refsets['class'], testsets['class'])
f1=f_measure(refsets['class'], testsets['class'])
print('precision:', prec)
print('recall:', rec)
print('F-measure:', f1)
all_f_measure.append(f1)
all_precision.append(prec)
all_recall.append(rec)
print('========Show top 10 most informative features========')
classifier.show_most_informative_features(10)
def ImplementLR(self):
print(
"~~~~~~~~~~~~~~~ Logistic Regression Classifier ~~~~~~~~~~~~~~~\n")
classifier = nltk.classify.SklearnClassifier(LogisticRegression())
classifier.train(trainFeatures)
print("Logistic Regression Classifier Training Completed")
#initiating referenceSets and testSets, Expected Array & Predicted Array for confusion matrix
referenceSets = collections.defaultdict(set)
testSets = collections.defaultdict(set)
expected_array = []
predicted_array = []
#assigning referenceSets & expected Array with correct labels & testsSets and predicted_array with predicted labels
for i, (features, label) in enumerate(testFeatures):
referenceSets[label].add(i)
expected_array.append(label)
predicted = classifier.classify(features)
predicted_array.append(predicted)
testSets[predicted].add(i)
# print ("\nLabel---->"+label+" i ----> "+str(i)+" referenceSet Label---->"+str(referenceSets[label])+"\n\n\n\n\n");
#prints metrics to show how well the feature selection did
print("Logistic Regression Classifier Test Results ")
print("")
print("Length of Training Features" + str(len(trainFeatures)))
print("Length of Test Features" + str(len(testFeatures)))
print('Accuracy:' +
str(nltk.classify.util.accuracy(classifier, testFeatures)))
print('Positive precision:',
str(precision(referenceSets['Positive'], testSets['Positive'])))
print('Positive recall:',
str(recall(referenceSets['Positive'], testSets['Positive'])))
print('Negative precision:',
str(precision(referenceSets['Negative'], testSets['Negative'])))
print('Negative recall:',
str(recall(referenceSets['Negative'], testSets['Negative'])))
print("~~~~~~~~~~~~~~~Classification report~~~~~~~~~~~~~~~\n",
classification_report(expected_array, predicted_array))
print("~~~~~~~~~~~~~~~Confusion matrix~~~~~~~~~~~~~~~\n",
confusion_matrix(expected_array, predicted_array))
print("plotting confusion Matrix")
def evaluate_classifier(featx):
stanford_pos_list = list()
stanford_neg_list = list()
with open(stanford_pos, 'r') as stanford_p:
for line in stanford_p:
stanford_pos_list.append(line.strip())
with open(stanford_neg, 'r') as stanford_n:
for line in stanford_n:
stanford_neg_list.append(line.strip())
stanford_p = stanford_pos_list[:5000]
stanford_n = stanford_neg_list[:5000]
negfeats = [(featx(nltk.word_tokenize(line)), 'neg')
for line in stanford_n]
posfeats = [(featx(nltk.word_tokenize(line)), 'pos')
for line in stanford_p]
negcutoff = int(len(negfeats) * 3 / 4)
poscutoff = int(len(posfeats) * 3 / 4)
trainfeats = negfeats[:negcutoff] + posfeats[:poscutoff]
testfeats = negfeats[negcutoff:] + posfeats[poscutoff:]
print('train on %d instances, test on %d instances' %
(len(trainfeats), len(testfeats)))
classifier = NaiveBayesClassifier.train(trainfeats)
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(testfeats):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
print('accuracy:', nltk.classify.util.accuracy(classifier, testfeats))
print('pos precision:', precision(refsets['pos'], testsets['pos']))
print('pos recall:', recall(refsets['pos'], testsets['pos']))
print('pos F-measure:', f_measure(refsets['pos'], testsets['pos']))
print('neg precision:', precision(refsets['neg'], testsets['neg']))
print('neg recall:', recall(refsets['neg'], testsets['neg']))
print('neg F-measure:', f_measure(refsets['neg'], testsets['neg']))
classifier.show_most_informative_features()
def calculate(classifier, feature_set):
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
print("Calculating refsets for precision and recall")
for i, (feats, label) in enumerate(feature_set):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
print('country precision:', metrics.precision(refsets['country'], testsets['country']))
print('country recall:', metrics.recall(refsets['country'], testsets['country']))
print('religion precision:', metrics.precision(refsets['religion'], testsets['religion']))
print('religion recall:', metrics.recall(refsets['religion'], testsets['religion']))
print('astronomy precision:', metrics.precision(refsets['astronomy'], testsets['astronomy']))
print('astronomy recall:', metrics.recall(refsets['astronomy'], testsets['astronomy']))
def print_results(classifier, featureset, results, name):
print '''
%s classifier results:
Classifier accuracy: %s
B Precision: %s
B Recall: %s
I Precision: %s
I Recall: %s
O Precision: %s
O Recall: %s
''' % (name,
accuracy(classifier, featureset),
precision(results[0]['B-SNP'], results[1]['B-SNP']),
recall(results[0]['B-SNP'], results[1]['B-SNP']),
precision(results[0]['I-SNP'], results[1]['I-SNP']),
recall(results[0]['I-SNP'], results[1]['I-SNP']),
precision(results[0]['O'], results[1]['O']),
recall(results[0]['O'], results[1]['O']))
def results(classifier, testing_set, training_set):
now = datetime.now()
# Trains classifier
classifier = classifier.train(training_set)
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
tp = 0
fp = 0
tn = 0
fn = 0
# Gets positive/false positives/negatives
for i, (features, label) in enumerate(testing_set):
refsets[label].add(i)
observed = classifier.classify(features)
testsets[observed].add(i)
if label == 'exp' and observed == 'exp':
tp += 1
elif label == 'non' and observed == 'non':
tn += 1
elif label == 'exp' and observed == 'non':
fn += 1
else:
fp += 1
print "Time training: " + str(datetime.now() - now)
print "True Positives: " + str(tp)
print "False Positives: " + str(fp)
print "True Negatives: " + str(tn)
print "False Negatives: " + str(fn)
print 'Explicit Precision: ', precision(refsets['exp'],
testsets['exp'])
print 'Explicit recall: ', recall(refsets['exp'], testsets['exp'])
print 'Explicit F-Score: ', f_measure(refsets['exp'], testsets['exp'])
print 'Non-Explicit Precision: ', precision(refsets['non'],
testsets['non'])
print 'Non-Explicit Recall: ', recall(refsets['non'], testsets['non'])
print 'Non-Explicit F-Score: ', f_measure(refsets['non'],
testsets['non'])
print "Accuracy percent: ", (nltk.classify.accuracy(
classifier, testing_set)) * 100
return classifier
def eval_stats(results):
'''
Compute recall, precision, and f-measure from passed results.
The expected format for results is a dictionary whose keys=<name of article>
and values=tuple (<test category>, <reference category>, <scores>), where:
test=category suggested by classifier, reference=pre-classified gold
category, scores=can be None or dictionary whose keys=category names and
values=matching score for this article.
'''
# Calculate number of correct matches
correct = 0
missed = defaultdict(tuple)
for article_name, (suggested, real, scores) in results.iteritems():
if suggested==real:
correct += 1
else:
missed[article_name] = (suggested, real)
success_ratio = correct / float(len(results))
print "Ratio: %0.3f" % success_ratio
# Print wrong matches
for name, (suggested, real) in missed.iteritems():
print "%s\t%s\t%s" % (name, suggested, real)
# Create sets of references / test classification for evaluation
cat_ref = defaultdict(set)
cat_test= defaultdict(set)
for name, (test_category, ref_category, scores) in results.iteritems():
cat_ref[ref_category].add(name) # gold-tagged categories
cat_test[test_category].add(name) # suggested categories
# Precision, recall, f-measure, support (num of reference articles in
# each category) for each category
print "\nCategory\tPrecision\tRecall\tF-measure\tSupport"
measures = defaultdict(tuple)
for category in cat_ref.keys():
cat_prec = metrics.precision(cat_ref[category], cat_test[category])
cat_rec = metrics.recall(cat_ref[category], cat_test[category])
cat_f = metrics.f_measure(cat_ref[category], cat_test[category])
cat_support = len(cat_ref[category])
measures[category] = (cat_prec, cat_rec, cat_f, cat_support)
print "%s\t%0.3f\t%0.3f\t%0.3f\t%d" % \
(category, cat_prec, cat_rec, cat_f, cat_support)
# Calculate precision, recall, f-measure for entire corpus:
# This is a weighted average of the values of separate categories
# SUM(product of all precisions, product of all supports)/sum(total number of supports)
avg_prec = weighted_average([(cat_measure[0], cat_measure[3]) for \
cat_measure in measures.values()])
avg_rec = weighted_average([(cat_measure[1], cat_measure[3]) for \
cat_measure in measures.values()])
avg_f = weighted_average([(cat_measure[2], cat_measure[3]) for \
cat_measure in measures.values()])
total_support = sum([cat_support[3] for cat_support in measures.values()])
print "%s\t%0.3f\t%0.3f\t%0.3f\t%d" % ("Total", avg_prec, avg_rec, avg_f, total_support)
def evaluate_precision_recall_fmeasure(corpus, category, tagger):
# get a list of the gold standard tags, and the tags set by the tagger.
gold = set(tag_list(corpus.tagged_sents(categories=category)))
test = set(
tag_list(apply_tagger(tagger,
corpus.tagged_sents(categories=category))))
# return the precision and recall of the evaluated model.
return [precision(gold, test), recall(gold, test), f_measure(gold, test)]
def ImplementLSVC(self):
print("~~~~~~~~~~~~~~~ Linear SVC Classifier ~~~~~~~~~~~~~~~\n")
classifier = nltk.classify.SklearnClassifier(LinearSVC())
classifier.train(trainFeatures)
print("Linear SVC Classifier Training Completed")
#initiates referenceSets and testSets
referenceSets = collections.defaultdict(set)
testSets = collections.defaultdict(set)
expected_array = []
predicted_array = []
#puts correctly labeled sentences in referenceSets and the predictively labeled version in testsets
for i, (features, label) in enumerate(testFeatures):
referenceSets[label].add(i)
expected_array.append(label)
predicted = classifier.classify(features)
predicted_array.append(predicted)
testSets[predicted].add(i)
#prints metrics to show how well the feature selection did
print("Linear SVC Classifier Test Results ")
print("")
print("Length of Training Features" + str(len(trainFeatures)))
print("Length of Test Features" + str(len(testFeatures)))
print('Accuracy:' +
str(nltk.classify.util.accuracy(classifier, testFeatures)))
print('Positive precision:',
str(precision(referenceSets['Positive'], testSets['Positive'])))
print('Positive recall:',
str(recall(referenceSets['Positive'], testSets['Positive'])))
print('Negative precision:',
str(precision(referenceSets['Negative'], testSets['Negative'])))
print('Negative recall:',
str(recall(referenceSets['Negative'], testSets['Negative'])))
print("~~~~~~~~~~~~~~~Classification report~~~~~~~~~~~~~~~\n",
classification_report(expected_array, predicted_array))
print("~~~~~~~~~~~~~~~Confusion matrix~~~~~~~~~~~~~~~\n",
confusion_matrix(expected_array, predicted_array))
print("")
def evaluate_features(feature_extractor, N, only_acc=False):
from nltk.corpus import movie_reviews
from nltk.classify import NaiveBayesClassifier as naive
from nltk.classify.util import accuracy
from nltk.metrics import precision, recall, f_measure
from sys import stdout
negative = movie_reviews.fileids('neg')
positive = movie_reviews.fileids('pos')
negfeats = [(feature_extractor(movie_reviews.sents(fileids=[f])),
'neg') for f in negative]
posfeats = [(feature_extractor(movie_reviews.sents(fileids=[f])),
'pos') for f in positive]
negtrain, negtest = stratifiedSamples(negfeats, N)
postrain, postest = stratifiedSamples(posfeats, N)
trainfeats = negtrain + postrain
testfeats = negtest + postest
classifier = naive.train(trainfeats)
if only_acc: return accuracy(classifier, testfeats)
print 'accuracy: {}'.format(accuracy(classifier, testfeats))
# Precision, Recall, F-measure
from collections import defaultdict
refsets = defaultdict(set)
testsets = defaultdict(set)
for i, (feats, label) in enumerate(testfeats):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
print 'pos precision:', precision(refsets['pos'], testsets['pos'])
print 'pos recall:', recall(refsets['pos'], testsets['pos'])
print 'pos F-measure:', f_measure(refsets['pos'], testsets['pos'])
print 'neg precision:', precision(refsets['neg'], testsets['neg'])
print 'neg recall:', recall(refsets['neg'], testsets['neg'])
print 'neg F-measure:', f_measure(refsets['neg'], testsets['neg'])
stdout.flush()
classifier.show_most_informative_features()
return classifier
def evaluate_features(feature_extractor, N, only_acc=False):
from nltk.corpus import movie_reviews
from nltk.classify import NaiveBayesClassifier as naive
from nltk.classify.util import accuracy
from nltk.metrics import precision, recall, f_measure
from sys import stdout
negative = movie_reviews.fileids('neg')
positive = movie_reviews.fileids('pos')
negfeats = [(feature_extractor(movie_reviews.sents(fileids=[f])), 'neg')
for f in negative]
posfeats = [(feature_extractor(movie_reviews.sents(fileids=[f])), 'pos')
for f in positive]
negtrain, negtest = stratifiedSamples(negfeats, N)
postrain, postest = stratifiedSamples(posfeats, N)
trainfeats = negtrain + postrain
testfeats = negtest + postest
classifier = naive.train(trainfeats)
if only_acc: return accuracy(classifier, testfeats)
print 'accuracy: {}'.format(accuracy(classifier, testfeats))
# Precision, Recall, F-measure
from collections import defaultdict
refsets = defaultdict(set)
testsets = defaultdict(set)
for i, (feats, label) in enumerate(testfeats):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
print 'pos precision:', precision(refsets['pos'], testsets['pos'])
print 'pos recall:', recall(refsets['pos'], testsets['pos'])
print 'pos F-measure:', f_measure(refsets['pos'], testsets['pos'])
print 'neg precision:', precision(refsets['neg'], testsets['neg'])
print 'neg recall:', recall(refsets['neg'], testsets['neg'])
print 'neg F-measure:', f_measure(refsets['neg'], testsets['neg'])
stdout.flush()
classifier.show_most_informative_features()
return classifier
def evaluate_features(self, feature_select):
#reading pre-labeled input and splitting into lines
posSentences = open('rt-polarity-pos.txt', 'r')
negSentences = open('rt-polarity-neg.txt', 'r')
posSentences = re.split(r'\n', posSentences.read())
negSentences = re.split(r'\n', negSentences.read())
posFeatures = []
negFeatures = []
#breaks up the sentences into lists of individual words (as selected by the input mechanism) and appends 'pos' or 'neg' after each list
for i in posSentences:
posWords = re.findall(r"[\w']+|[.,!?;]", i)
posWords = [feature_select(posWords), 'pos']
posFeatures.append(posWords)
for i in negSentences:
negWords = re.findall(r"[\w']+|[.,!?;]", i)
negWords = [feature_select(negWords), 'neg']
negFeatures.append(negWords)
#selects 3/4 of the features to be used for training and 1/4 to be used for testing
posCutoff = int(math.floor(len(posFeatures)*3/4))
negCutoff = int(math.floor(len(negFeatures)*3/4))
trainFeatures = posFeatures[:posCutoff] + negFeatures[:negCutoff]
testFeatures = posFeatures[posCutoff:] + negFeatures[negCutoff:]
#Training Phase:
classifier = NaiveBayesClassifier.train(trainFeatures)
referenceSets = collections.defaultdict(set)
testSets = collections.defaultdict(set)
#Testing Phase:
for i, (features, label) in enumerate(testFeatures):
referenceSets[label].add(i)
predicted = classifier.classify(features)
testSets[predicted].add(i)
print 'Trained on %d instances, Tested on %d instances' % (len(trainFeatures), len(testFeatures))
print 'Accuracy:', nltk.classify.util.accuracy(classifier, testFeatures)
print 'Positive Precision:', precision(referenceSets['pos'], testSets['pos'])
print 'Positive Recall:', recall(referenceSets['pos'], testSets['pos'])
print 'Negative Precision:', precision(referenceSets['neg'], testSets['neg'])
print 'Negative Recall:', recall(referenceSets['neg'], testSets['neg'])
def calcAllClassesRecall(classSet, refsets, testsets):
rSum = 0.0
denominator = 0
for category in classSet:
num = recall(refsets[category], testsets[category])
if num is None:
continue
rSum += num
denominator += 1
return rSum / denominator
def calcAllClassesRecall(classSet, refsets, testsets):
rSum = 0.0
denominator = 0
for category in classSet:
num = recall(refsets[category], testsets[category])
if num is None:
continue
rSum += num
denominator += 1
return rSum/denominator
def precision_recall(classifier, testfeats):
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(testfeats):
refsets[label].add(i)
precisions = {}
recalls = {}
for label in classifier.labels():
precisions[label] = metrics.precision(refsets[label], testsets[label])
recalls[label] = metrics.recall(refsets[label], testsets[label])
return precisions, recalls
def precision_recall(classifier, testfeats):
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(testfeats):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
precisions = {}
recalls = {}
for label in classifier.labels():
precisions[label] = metrics.precision(refsets[label], testsets[label])
recalls[label] = metrics.recall(refsets[label], testsets[label])
return precisions, recalls
def main():
global best_words
tweets = get_tweets_from_db()
tweet_list = tweets[1000:1599000]
test_list = tweets[:1000]+ tweets[1599000:]
word_scores = create_word_scores()
best_words = find_best_words(word_scores, 500000)
f = open('bestwords.pickle', 'wb')
pickle.dump(best_words, f)
f.close()
training_set = classify.apply_features(best_word_features, tweet_list)
print "extracted features"
# train the classifier with the training set
classifier = NaiveBayesClassifier.train(training_set)
print "trained classifier"
# create the pickle file
f = open('NBclassifier_new.pickle', 'wb')
pickle.dump(classifier, f)
f.close()
print "created pickle"
# test for precision and recall
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
test_set = classify.apply_features(best_word_features, test_list)
for i, (feats, label) in enumerate(test_set):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
print 'neg precision:', metrics.precision(refsets['0'], testsets['0'])
print 'neg recall:', metrics.recall(refsets['0'], testsets['0'])
print 'pos precision:', metrics.precision(refsets['4'], testsets['4'])
print 'pos recall:', metrics.recall(refsets['4'], testsets['4'])
# test_set = classify.apply_features(extract_features, test_list)
# print "extracted features"
print classify.accuracy(classifier, test_set)
print classifier.show_most_informative_features(30)
def evaluate(classifier, evalFeats, labels):
#old eval without cross Validation
try:
print('accuracy: %f' % nltk.classify.util.accuracy(classifier, evalFeats))
except ZeroDivisionError:
print('accuracy: 0')
refsets, testsets = ref_test_sets(classifier, evalFeats)
for label in labels:
ref = refsets[label]
test = testsets[label]
print('%s precision: %f' % (label, precision(ref, test) or 0))
print('%s recall: %f' % (label, recall(ref, test) or 0))
print('%s f-measure: %f' % (label, f_measure(ref, test) or 0))
def evaluation(test_set, classifier):
"""Evaluate the classifier with the test set. Print the accuracy,
precision, recall and f-measure."""
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (featureset, label) in enumerate(test_set):
refsets[label].add(i)
observed = classifier.classify(featureset)
testsets[observed].add(i)
print('Evaluation Results')
print("\t\t\t{:<20}{:0.2f}".format('classifier accuracy', accuracy(classifier, test_set)))
print("\t\t\t{:<20}{:0.2f}".format('precision male', precision(refsets['male'], testsets['male'])))
print("\t\t\t{:<20}{:0.2f}".format('precision female', precision(refsets['female'], testsets['female'])))
print("\t\t\t{:<20}{:0.2f}".format('recall male', recall(refsets['male'], testsets['male'])))
print("\t\t\t{:<20}{:0.2f}".format('recall female', recall(refsets['female'], testsets['female'])))
print("\t\t\t{:<20}{:0.2f}".format('f_measure male', f_measure(refsets['male'], testsets['male'])))
print("\t\t\t{:<20}{:0.2f}".format('f_measure female', f_measure(refsets['female'], testsets['female'])))
print()
def assess_classifier(classifier, test_set, text):
accuracy = nltk.classify.accuracy(classifier, test_set)
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(test_set):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
pos_pre = precision(refsets['positive'], testsets['positive'])
pos_rec = recall(refsets['positive'], testsets['positive'])
pos_fme = f_measure(refsets['positive'], testsets['positive'])
neg_pre = precision(refsets['negative'], testsets['negative'])
neg_rec = recall(refsets['negative'], testsets['negative'])
neg_fme = f_measure(refsets['negative'], testsets['negative'])
neu_pre = precision(refsets['neutral'], testsets['neutral'])
neu_rec = recall(refsets['neutral'], testsets['neutral'])
neu_fme = f_measure(refsets['negative'], testsets['neutral'])
return [
text, accuracy, pos_pre, pos_rec, pos_fme, neg_pre, neg_rec, neg_fme,
neu_pre, neu_rec, neu_fme
]
def evaluation(test_set, classifier):
"""Evaluate the classifier with the test set. Print the accuracy,
precision, recall and f-measure."""
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(test_set):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
print('Accuracy:', accuracy(classifier, test_set))
print('Precision:', precision(refsets['MALE'], testsets['MALE']))
print('Recall:', recall(refsets['MALE'], testsets['MALE']))
print('F Measure:', f_measure(refsets['MALE'], testsets['MALE']))
def precision_recall(classifier, testfeats):
""" Calculates and returns the precision and recall for a given classifier """
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(testfeats):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
precisions = {}
recalls = {}
for label in classifier.labels():
precisions[label] = precision(refsets[label], testsets[label])
recalls[label] = recall(refsets[label], testsets[label])
return precisions, recalls
def measure(classifier, testfeats, alpha=0.5):
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(testfeats):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
precisions = {}
recalls = {}
f_measures = {}
for label in classifier.labels():
precisions[label] = metrics.precision(refsets[label], testsets[label])
recalls[label] = metrics.recall(refsets[label], testsets[label])
f_measures[label] = metrics.f_measure(refsets[label], testsets[label], alpha)
return precisions, recalls, f_measures
def precision_recall(classifier, testfeats):
#gives precision and recall of classifiers
#precision = lack of false positives
#recall = lack of false negatives
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(testfeats):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
precisions = {}
recalls = {}
for label in classifier.labels():
precisions[label] = precision(refsets[label], testsets[label])
recalls[label] = recall(refsets[label], testsets[label])
return precisions, recalls
def evaluate_precision_recall_f_measure(self):
'''Evaluate precision, recall and f1 measure'''
scores = dict(prec_pos=[], rec_pos=[], fmeas_pos=[], prec_neg=[], rec_neg=[], fmeas_neg=[])
lfeats = self.label_feats_from_corpus()
for i in range(1, 10):
train_feats, test_feats, nb_classifier = self\
.__get_elements_for_classification(lfeats, train_number=i, classifying=False)
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(test_feats):
refsets[label].add(i)
observed = nb_classifier.classify(feats)
testsets[observed].add(i)
precisions = {}
recalls = {}
f_measure = {}
for label in nb_classifier.labels():
precisions[label] = metrics.precision(
refsets[label], testsets[label]
)
recalls[label] = metrics.recall(refsets[label], testsets[label])
f_measure[label] = metrics.f_measure(
refsets[label], testsets[label]
)
#print nb_classifier.show_most_informative_features(n=20)
scores["prec_pos"].append(precisions["pos"])
scores["prec_neg"].append(precisions["neg"])
scores["rec_pos"].append(recalls["pos"])
scores["rec_neg"].append(recalls["neg"])
scores["fmeas_pos"].append(f_measure["pos"])
scores["fmeas_neg"].append(f_measure["neg"])
scores["prec_pos"] = sum(scores["prec_pos"]) / len(scores["prec_pos"])
scores["prec_neg"] = sum(scores["prec_neg"]) / len(scores["prec_neg"])
scores["rec_pos"] = sum(scores["rec_pos"]) / len(scores["rec_pos"])
scores["rec_neg"] = sum(scores["rec_neg"]) / len(scores["rec_neg"])
scores["fmeas_pos"] = sum(scores["fmeas_pos"]) / len(scores["fmeas_pos"])
scores["fmeas_neg"] = sum(scores["fmeas_neg"]) / len(scores["fmeas_neg"])
return scores
def evaluate_features(feature_select):
posFeatures = []
negFeatures = []
#http://stackoverflow.com/questions/367155/splitting-a-string-into-words-and-punctuation
#breaks up the sentences into lists of individual words (as selected by the input mechanism) and appends 'pos' or 'neg' after each list
with open('short_reviews/positive.txt', 'r') as posSentences:
for i in posSentences:
posWords = re.findall(r"[\w']+|[.,!?;]", i.rstrip())
posWords = [feature_select(posWords), 'pos']
posFeatures.append(posWords)
with open('short_reviews/negative.txt', 'r') as negSentences:
for i in negSentences:
negWords = re.findall(r"[\w']+|[.,!?;]", i.rstrip())
negWords = [feature_select(negWords), 'neg']
negFeatures.append(negWords)
#selects 3/4 of the features to be used for training and 1/4 to be used for testing
posCutoff = int(math.floor(len(posFeatures) * 3 / 4))
negCutoff = int(math.floor(len(negFeatures) * 3 / 4))
trainFeatures = posFeatures[:posCutoff] + negFeatures[:negCutoff]
testFeatures = posFeatures[posCutoff:] + negFeatures[negCutoff:]
#trains a Naive Bayes Classifier
classifier = NaiveBayesClassifier.train(trainFeatures)
#initiates referenceSets and testSets
referenceSets = collections.defaultdict(set)
testSets = collections.defaultdict(set)
#puts correctly labeled sentences in referenceSets and the predictively labeled version in testsets
for i, (features, label) in enumerate(testFeatures):
referenceSets[label].add(i)
predicted = classifier.classify(features)
testSets[predicted].add(i)
#prints metrics to show how well the feature selection did
print('train on %d instances, test on %d instances' %
(len(trainFeatures), len(testFeatures)))
print('accuracy:', nltk.classify.util.accuracy(classifier, testFeatures))
print('pos precision:', precision(referenceSets['pos'], testSets['pos']))
print('pos recall:', recall(referenceSets['pos'], testSets['pos']))
print('neg precision:', precision(referenceSets['neg'], testSets['neg']))
print('neg recall:',
nltk.metrics.recall(referenceSets['neg'], testSets['neg']))
classifier.show_most_informative_features(10)
def recall(self, reference):
"""
Return the recall of an aligned sentence with respect to a
"gold standard" reference ``AlignedSent``.
:type reference: AlignedSent or Alignment
:param reference: A "gold standard" reference aligned sentence.
:rtype: float or None
"""
# Get alignments in set of 2-tuples form
# The "sure" recall is used so we don't penalize for missing an
# alignment that was only marked as "possible".
align = self.alignment
if isinstance(reference, AlignedSent):
sure = reference.alignment
else:
sure = Alignment(reference)
# Call NLTKs existing functions for recall
return recall(sure, align)
#script to validate coding import cPickle as pickle import sys from nltk.metrics import accuracy, ConfusionMatrix, precision, recall, f_measure from collections import defaultdict import classifier if __name__=='__main__': validation_pickle=sys.argv[1] classifier_pickle=sys.argv[2] validation_set=pickle.load(open(validation_pickle, 'rb')) c=pickle.load(open(classifier_pickle, 'rb')) reference=defaultdict(set) observed=defaultdict(set) for i, (tweet, label) in enumerate(validation_set): reference[label].add(i) observation=c.classify(tweet) observed[observation].add(i) print "accuracy: %s" % accuracy(observed, reference) print "pos precision: %s" % precision(reference['positive'], observed['positive']) print "pos recall: %s" % recall(reference['positive'], observed['positive']) print "pos f-measure: %s" % f_measure(reference['positive'], observed['positive']) print "neg precision: %s" % precision(reference['negative'], observed['negative']) print "neg recall: %s" % recall(reference['negative'], observed['negative']) print "neg f-measure: %s" % f_measure(reference['negative'], observed['negative'])
def recall(self):
return recall(self._reference, self._test)
##pprint.pprint(results)
#pprint(results)
import sys
#sys.exit()
print '''
Classifier accuracy (Bayes): %s
B Precision (Bayes): %s
B Recall (Bayes): %s
I Precision (Bayes): %s
I Recall (Bayes): %s
O Precision (Bayes): %s
O Recall (Bayes): %s
''' % (accuracy(bayes_classifier, test_featureset),
precision(results[0]['B-SNP'], results[1]['B-SNP']),
recall(results[0]['B-SNP'], results[1]['B-SNP']),
precision(results[0]['I-SNP'], results[1]['I-SNP']),
recall(results[0]['I-SNP'], results[1]['I-SNP']),
precision(results[0]['O'], results[1]['O']),
recall(results[0]['O'], results[1]['O']))
#bayes_classifier.show_most_informative_features(10)
sys.exit()
maxent_classifier = nltk.classify.MaxentClassifier.train(training_featureset)
maxent_results = get_results(maxent_classifier)
print '''
Classifier accuracy (MaxEnt): %s
B Precision (MaxEnt): %s
def avaliate_new_classifier(featureSet):
print("Vamos treinar o classificador agora!")
print("\n")
#random.shuffle(featureSet)
#Cada um tem 197
positive_tweets = featureSet[:196]
#Misturando as paradas pra nao ficar testando só os mesmos últimos
random.shuffle(positive_tweets)
#print(featureSet[7185])
#Pra pegar 7185 do pos e 7185 do negativo mas o negativo tem 7213
negative_tweets = featureSet[196:293]
random.shuffle(negative_tweets)
neutral_tweets = featureSet[293:]
random.shuffle(neutral_tweets)
#Agora vou dividir cada classe em um conjunto de referencia e outro de teste
pos_cutoff = len(positive_tweets)*3/4
neg_cutoff = len(negative_tweets)*3/4
neu_cutoff = len(neutral_tweets)*3/4
# 75% dos tweets vao pra ser de referencia(treinamento) e o resto pra teste
pos_references = positive_tweets[:pos_cutoff]
pos_tests = positive_tweets[pos_cutoff:]
neg_references = negative_tweets[:neg_cutoff]
neg_tests = negative_tweets[neg_cutoff:]
neu_references = neutral_tweets[:neu_cutoff]
neu_tests = neutral_tweets[neu_cutoff:]
#COnjunto de treinamento e de testes pra calcular a accuracy
training_set = pos_references + neg_references + neu_references
testing_set = pos_tests + neg_tests + neu_tests
start_time = time.time()
global classifier
print("Comecou a treina-lo agora!")
#training_set2 = [(t,l) for (t,l,twe) in training_set]
classifier = nltk.NaiveBayesClassifier.train(training_set)
#testing_set2 = [(t,l) for (t,l,twe) in testing_set]
print("Naive Bayes Algo accuracy:", (nltk.classify.accuracy(classifier, testing_set)) * 100)
classifier.show_most_informative_features(30)
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(testing_set):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
print 'pos precision:', precision(refsets['pos'], testsets['pos'])
print 'pos recall:', recall(refsets['pos'], testsets['pos'])
print 'pos F-measure:', f_measure(refsets['pos'], testsets['pos'])
print 'neg precision:', precision(refsets['neg'], testsets['neg'])
print 'neg recall:', recall(refsets['neg'], testsets['neg'])
print 'neg F-measure:', f_measure(refsets['neg'], testsets['neg'])
print 'neutral precision:', precision(refsets['neutral'], testsets['neutral'])
print 'neutral recall:', recall(refsets['neutral'], testsets['neutral'])
print 'neutral F-measure:', f_measure(refsets['neutral'], testsets['neutral'])
print("--- Classifier executed in %s seconds ---" % (time.time() - start_time))
def avaliate_classifiers(featureSet):
print("Vamos treinar o classificador agora!")
print("\n")
#random.shuffle(featureSet)
#Vai fazer o calculo de recall e precision
# You need to build 2 sets for each classification label:
# a reference set of correct values, and a test set of observed values.
#Os primeiros 6686 + 500(dia 14) tweets sao positivos e resto(6757 + 500(dia 14)) negativo
positive_tweets = featureSet[:7185]
#Misturando as paradas pra nao ficar testando só os mesmos últimos
random.shuffle(positive_tweets)
#print(featureSet[7185])
#Pra pegar 7185 do pos e 7185 do negativo mas o negativo tem 7213
negative_tweets = featureSet[7185:14372]
random.shuffle(negative_tweets)
#Agora vou dividir cada classe em um conjunto de referencia e outro de teste
pos_cutoff = len(positive_tweets)*3/4
neg_cutoff = len(negative_tweets)*3/4
# 75% dos tweets vao pra ser de referencia(treinamento) e o resto pra teste
pos_references = positive_tweets[:pos_cutoff]
pos_tests = positive_tweets[pos_cutoff:]
neg_references = negative_tweets[:neg_cutoff]
neg_tests = negative_tweets[neg_cutoff:]
#COnjunto de treinamento e de testes pra calcular a accuracy
training_set = pos_references + neg_references
testing_set = pos_tests + neg_tests
start_time = time.time()
global classifier
print("Comecou a treina-lo agora!")
#training_set2 = [(t,l) for (t,l,twe) in training_set]
classifier = nltk.NaiveBayesClassifier.train(training_set)
#testing_set2 = [(t,l) for (t,l,twe) in testing_set]
print("Naive Bayes Algo accuracy:", (nltk.classify.accuracy(classifier, testing_set)) * 100)
classifier.show_most_informative_features(30)
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
# for i, (feats, label, l) in enumerate(testing_set):
# refsets[label].add(i)
# observed = classifier.classify(feats)
# testsets[observed].add(i)
# print("--"*200)
# print()
# print("Classified as: ",observed)
# print()
# print(l)
# print()
# print("--"*200)
# raw_input("Press any key to continue:")
print 'pos precision:', precision(refsets['pos'], testsets['pos'])
print 'pos recall:', recall(refsets['pos'], testsets['pos'])
print 'pos F-measure:', f_measure(refsets['pos'], testsets['pos'])
print 'neg precision:', precision(refsets['neg'], testsets['neg'])
print 'neg recall:', recall(refsets['neg'], testsets['neg'])
print 'neg F-measure:', f_measure(refsets['neg'], testsets['neg'])
print("--- Classifier executed in %s seconds ---" % (time.time() - start_time))
def cross_fold(instances, trainf, testf, folds=10, trace=1, metrics=True, informative=0):
if folds < 2:
raise ValueError('must have at least 3 folds')
# ensure isn't an exhaustible iterable
instances = list(instances)
# randomize so get an even distribution, in case labeled instances are
# ordered by label
random.shuffle(instances)
l = len(instances)
step = l / folds
if trace:
print('step %d over %d folds of %d instances' % (step, folds, l))
accuracies = []
precisions = collections.defaultdict(list)
recalls = collections.defaultdict(list)
f_measures = collections.defaultdict(list)
for f in range(folds):
if trace:
print('\nfold %d' % (f+1))
print('-----%s' % ('-'*len('%s' % (f+1))))
start = f * step
end = start + step
train_instances = instances[:start] + instances[end:]
test_instances = instances[start:end]
if trace:
print('training on %d:%d + %d:%d' % (0, start, end, l))
obj = trainf(train_instances)
if trace:
print('testing on %d:%d' % (start, end))
if metrics:
refsets, testsets = ref_test_sets(obj, test_instances)
for key in set(refsets.keys() + testsets.keys()):
ref = refsets[key]
test = testsets[key]
p = precision(ref, test) or 0
r = recall(ref, test) or 0
f = f_measure(ref, test) or 0
precisions[key].append(p)
recalls[key].append(r)
f_measures[key].append(f)
if trace:
print('%s precision: %f' % (key, p))
print('%s recall: %f' % (key, r))
print('%s f-measure: %f' % (key, f))
accuracy = testf(obj, test_instances)
if trace:
print('accuracy: %f' % accuracy)
accuracies.append(accuracy)
if trace and informative and hasattr(obj, 'show_most_informative_features'):
obj.show_most_informative_features(informative)
if trace:
print('\nmean and variance across folds')
print('------------------------------')
print('accuracy mean: %f' % (sum(accuracies) / folds))
print('accuracy variance: %f' % array(accuracies).var())
for key, ps in iteritems(precisions):
print('%s precision mean: %f' % (key, sum(ps) / folds))
print('%s precision variance: %f' % (key, array(ps).var()))
for key, rs in iteritems(recalls):
print('%s recall mean: %f' % (key, sum(rs) / folds))
print('%s recall variance: %f' % (key, array(rs).var()))
for key, fs in iteritems(f_measures):
print('%s f_measure mean: %f' % (key, sum(fs) / folds))
print('%s f_measure variance: %f' % (key, array(fs).var()))
return accuracies, precisions, recalls, f_measures
# print the classification results
print 'Dictionary : ', dictionary.get_name(), '\n'
print ConfusionMatrix(gold_standard,results).pp()
print 'Accuracy: ', accuracy(gold_standard,results)
for c in [0,1,-1]:
print 'Metrics for class ', c
gold = set()
test = set()
for i,x in enumerate(gold_standard):
if x == c:
gold.add(i)
for i,x in enumerate(results):
if x == c:
test.add(i)
print 'Precision: ', precision(gold, test)
print 'Recall : ', recall(gold, test)
print 'F_measure: ', f_measure(gold, test)
print '\n\n'
#################### Sentences classification ##########################
# Not reported in the paper because LIWC doesn't have neutral class
positive_sents = [reli.words_sentence_pos(s) for s in reli.sents(polarity='positive')]
negative_sents = [reli.words_sentence_pos(s) for s in reli.sents(polarity='negative')]
neutral_sents = [reli.words_sentence_pos(s) for s in reli.sents(polarity='neutral')]
print '#########################################################################'
print '###################### Sentences classification #########################'
if not args.no_precision or not args.no_recall or not args.no_fmeasure: if args.multi and args.binary: refsets, testsets = scoring.multi_ref_test_sets(classifier, test_feats) else: refsets, testsets = scoring.ref_test_sets(classifier, test_feats) for label in labels: ref = refsets[label] test = testsets[label] if not args.no_precision: print '%s precision: %f' % (label, precision(ref, test) or 0) if not args.no_recall: print '%s recall: %f' % (label, recall(ref, test) or 0) if not args.no_fmeasure: print '%s f-measure: %f' % (label, f_measure(ref, test) or 0) if args.show_most_informative and args.algorithm != 'DecisionTree' and not (args.multi and args.binary): print '%d most informative features' % args.show_most_informative classifier.show_most_informative_features(args.show_most_informative) ############## ## pickling ## ############## if not args.no_pickle: if args.filename: fname = os.path.expanduser(args.filename)
texts = list(lif(categorized_corpus, label))
stop = int(len(texts) * args.fraction)
for t in texts[:stop]:
feat = bag_of_words(norm_words(t))
feats.append(feat)
test_feats.append((feat, label))
print "accuracy:", accuracy(classifier, test_feats)
refsets, testsets = scoring.ref_test_sets(classifier, test_feats)
for label in labels:
ref = refsets[label]
test = testsets[label]
print "%s precision: %f" % (label, precision(ref, test) or 0)
print "%s recall: %f" % (label, recall(ref, test) or 0)
print "%s f-measure: %f" % (label, f_measure(ref, test) or 0)
else:
if args.instances == "sents":
texts = categorized_corpus.sents()
total = len(texts)
elif args.instances == "paras":
texts = (itertools.chain(*para) for para in categorized_corpus.paras())
total = len(categorized_corpus.paras)
elif args.instances == "files":
texts = (categorized_corpus.words(fileids=[fid]) for fid in categorized_corpus.fileids())
total = len(categorized_corpus.fileids())
stop = int(total * args.fraction)
feats = (bag_of_words(norm_words(i)) for i in itertools.islice(texts, stop))
def train_classifiers(posFeatures,negFeatures):
#selects 3/4 of the features to be used for training and 1/4 to be used for testing
posCutoff = int(math.floor(len(posFeatures)*3/4))
negCutoff = int(math.floor(len(negFeatures)*3/4))
trainFeatures = posFeatures[:posCutoff] + negFeatures[:negCutoff]
testFeatures = posFeatures[posCutoff:] + negFeatures[negCutoff:]
#trains a Naive Bayes Classifier
print ("----------------Naive Bayes Classifier-----------")
classifier = NaiveBayesClassifier.train(trainFeatures)
#initiates referenceSets and testSets
referenceSets = collections.defaultdict(set)
testSets = collections.defaultdict(set)
#puts correctly labeled sentences in referenceSets and the predictively labeled version in testsets
for i, (features, label) in enumerate(testFeatures):
referenceSets[label].add(i)
predicted = classifier.classify(features)
testSets[predicted].add(i)
#prints metrics to show how well the feature selection did
print ('train on %d instances, test on %d instances' % (len(trainFeatures), len(testFeatures)))
print ('Original Naive Bayes Accuracy:', (nltk.classify.util.accuracy(classifier, testFeatures))*100)
print ('pos precision:', precision(referenceSets['pos'], testSets['pos']))
print ('pos recall:', recall(referenceSets['pos'], testSets['pos']))
print ('neg precision:',precision(referenceSets['neg'], testSets['neg']))
print ('neg recall:', recall(referenceSets['neg'], testSets['neg']))
classifier.show_most_informative_features(10)
#Pickle the algorithm for future use
save_classifier = open("pickled_algos/originalnaivebayes.pickle","wb")
pickle.dump(classifier, save_classifier)
save_classifier.close()
MNB_classifier = SklearnClassifier(MultinomialNB())
MNB_classifier.train(trainFeatures)
print("MNB_classifier accuracy percent:", (nltk.classify.accuracy(MNB_classifier, testFeatures))*100)
#Pickle the algorithm for future use
save_classifier = open("pickled_algos/MNB_classifier.pickle","wb")
pickle.dump(MNB_classifier, save_classifier)
save_classifier.close()
BernoulliNB_classifier = SklearnClassifier(BernoulliNB())
BernoulliNB_classifier.train(trainFeatures)
print("BernoulliNB_classifier accuracy percent:", (nltk.classify.accuracy(BernoulliNB_classifier, testFeatures))*100)
#Pickle the algorithm for future use
save_classifier = open("pickled_algos/BernoulliNB_classifier.pickle","wb")
pickle.dump(BernoulliNB_classifier, save_classifier)
save_classifier.close()
LogisticRegression_classifier = SklearnClassifier(LogisticRegression())
LogisticRegression_classifier.train(trainFeatures)
print("LogisticRegression_classifier accuracy percent:", (nltk.classify.accuracy(LogisticRegression_classifier, testFeatures))*100)
#Pickle the algorithm for future use
save_classifier = open("pickled_algos/LogisticRegression_classifier.pickle","wb")
pickle.dump(LogisticRegression_classifier, save_classifier)
save_classifier.close()
LinearSVC_classifier = SklearnClassifier(LinearSVC())
LinearSVC_classifier.train(trainFeatures)
print("LinearSVC_classifier accuracy percent:", (nltk.classify.accuracy(LinearSVC_classifier, testFeatures))*100)
#Pickle the algorithm for future use
save_classifier = open("pickled_algos/LinearSVC_classifier.pickle","wb")
pickle.dump(LinearSVC_classifier, save_classifier)
save_classifier.close()
SGDC_classifier = SklearnClassifier(SGDClassifier())
SGDC_classifier.train(trainFeatures)
print("SGDClassifier accuracy percent:",nltk.classify.accuracy(SGDC_classifier, testFeatures)*100)
#Pickle the algorithm for future use
save_classifier = open("pickled_algos/SGDC_classifier.pickle","wb")
pickle.dump(SGDC_classifier, save_classifier)
save_classifier.close()
Dec_Tree_Classifier = SklearnClassifier(DecisionTreeClassifier())
Dec_Tree_Classifier.train(trainFeatures)
print("DecisionTreeClassifier Accuracy:",(nltk.classify.accuracy(Dec_Tree_Classifier,testFeatures))*100)
#Pickle the algorithm for future use
save_classifier = open("pickled_algos/decision_tree.pickle","wb")
pickle.dump(Dec_Tree_Classifier, save_classifier)
save_classifier.close()
"""
# Grad_Boost_Classifier = SklearnClassifier(GradientBoostingClassifier())
# Grad_Boost_Classifier.train(trainFeatures)
# print("Gradient Boosting Classifier Accuracy:", (nltk.classify.accuracy(Grad_Boost_Classifier,testFeatures))*100)
"""
Random_Forest_Classifier = SklearnClassifier(RandomForestClassifier())
Random_Forest_Classifier.train(trainFeatures)
print("Random Forest Classifier Accuracy:",(nltk.classify.accuracy(Random_Forest_Classifier,testFeatures
))*100)
#Pickle the algorithm for future use
save_classifier = open("pickled_algos/random_forest.pickle","wb")
pickle.dump(Random_Forest_Classifier, save_classifier)
save_classifier.close()
Ada_Boost_Classifier = SklearnClassifier(AdaBoostClassifier())
Ada_Boost_Classifier.train(trainFeatures)
print("Ada Boost Classifier Accuracy:",(nltk.classify.accuracy(Ada_Boost_Classifier,testFeatures))*100)
#Pickle the algorithm for future use
save_classifier = open("pickled_algos/Ada_Boost.pickle","wb")
pickle.dump(Ada_Boost_Classifier, save_classifier)
save_classifier.close()
voted_classifier = VoteClassifier(classifier,
LinearSVC_classifier,
MNB_classifier,
BernoulliNB_classifier,
LogisticRegression_classifier,
Random_Forest_Classifier,
Ada_Boost_Classifier
)
print("Voted classifier accuracy percent:", (nltk.classify.accuracy(voted_classifier, testFeatures))*100)
# The voted classifier could not be pickled. Check this later!
return trainFeatures,testFeatures
def evaluate_features(feature_select, classifier_sel):
posFeatures = []
negFeatures = []
# http://stackoverflow.com/questions/367155/splitting-a-string-into-words-and-punctuation
# breaks up the sentences into lists of individual words (as selected by the input mechanism) and appends 'pos' or 'neg' after each list
with open(RT_POLARITY_POS_FILE, 'r') as posSentences:
for i in posSentences:
i = clean_text(i)
posWords = [w for w in i.lower().split() if w not in stopWords]
# posWords = re.findall(r"[\w']+|[.,!?;]", i.rstrip())
posWords = [feature_select(posWords), 'pos']
posFeatures.append(posWords)
with open(RT_POLARITY_NEG_FILE, 'r') as negSentences:
for i in negSentences:
i = clean_text(i)
negWords = [w for w in i.lower().split() if w not in stopWords]
# negWords = re.findall(r"[\w']+|[.,!?;]", i.rstrip())
negWords = [feature_select(negWords), 'neg']
negFeatures.append(negWords)
# selects 3/4 of the features to be used for training and 1/4 to be used for testing
if (DATA_FLAG == 'kooshas_data'):
trainFeatures = posFeatures + negFeatures
neg_test, pos_test, neut_test = get_features(testing_data, no_classes=2, feat_select=feature_select)
testFeatures = pos_test + neg_test # for three class data add neutFeat
else:
posCutoff = int(math.floor(len(posFeatures) * 4 / 5))
negCutoff = int(math.floor(len(negFeatures) * 4 / 5))
trainFeatures = posFeatures[:posCutoff] + negFeatures[:negCutoff]
testFeatures = posFeatures[posCutoff:] + negFeatures[negCutoff:]
aa, bb, cc = get_features(testing_data, no_classes=2, feat_select=feature_select)
testFeatures = aa + bb
# initiates referenceSets and testSets
referenceSets = collections.defaultdict(set)
testSets = collections.defaultdict(set)
# trains a Classifier
if classifier_sel == 'NB':
classifier = NaiveBayesClassifier.train(trainFeatures)
# puts correctly labeled sentences in referenceSets and the predictively labeled version in testsets
for i, (features, label) in enumerate(testFeatures):
referenceSets[label].add(i)
predicted = classifier.classify(features)
testSets[predicted].add(i)
# prints metrics to show how well the feature selection did
print ('train on %d instances, test on %d instances' % (len(trainFeatures), len(testFeatures)))
print ('accuracy:', nltk.classify.util.accuracy(classifier, testFeatures))
for i, (features, label) in enumerate(testFeatures):
referenceSets[label].add(i)
predicted = classifier.classify(features)
testSets[predicted].add(i)
print ('pos precision:', precision(referenceSets['pos'], testSets['pos']))
print ('pos recall:', recall(referenceSets['pos'], testSets['pos']))
print ('neg precision:', precision(referenceSets['neg'], testSets['neg']))
print ('neg recall:', recall(referenceSets['neg'], testSets['neg']))
classifier.show_most_informative_features(10)
elif classifier_sel == 'MaxEnt':
get_performance(LogisticRegression(), trainFeatures, testFeatures)
elif classifier_sel == 'all_classifiers':
get_performance(MultinomialNB(), trainFeatures, testFeatures)
get_performance(BernoulliNB(), trainFeatures, testFeatures)
get_performance(LogisticRegression(), trainFeatures, testFeatures)
get_performance(SGDClassifier(), trainFeatures, testFeatures)
get_performance(SVC(), trainFeatures, testFeatures)
get_performance(LinearSVC(), trainFeatures, testFeatures)
get_performance(NuSVC(kernel='rbf', nu=1), trainFeatures, testFeatures)
elif classifier_sel == 'SVM': # use SVM
SVC_classifier = SklearnClassifier(SVC())
classifier = SVC_classifier.train(trainFeatures)
print("SVC_classifier accuracy:",
(nltk.classify.accuracy(classifier, testFeatures)) * 100)
for i, (features, label) in enumerate(testFeatures):
referenceSets[label].add(i)
predicted = classifier.classify(features)
testSets[predicted].add(i)
get_performance(classifier, referenceSets, testSets)
# Now create the data structure for model evaluation
#
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(testfeats):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
#print len(refsets)
#print len(testsets)
#print refsets
precisions = {}
recalls = {}
for label in classifier.labels():
precisions[label] = metrics.precision(refsets[label],testsets[label])
recalls[label] = metrics.recall(refsets[label], testsets[label])
#
# Let us calculate Precision & Recall and compare with nltk
#
# Luckily the data structures are symmetric
#
c_00=len(refsets[labels[0]].intersection(testsets[labels[0]]))
c_01=len(refsets[labels[0]].intersection(testsets[labels[1]]))
c_10=len(refsets[labels[1]].intersection(testsets[labels[0]]))
c_11=len(refsets[labels[1]].intersection(testsets[labels[1]]))
#
print ' | H | S |'
print '--|-------|-------|'
print 'H | %5d | %5d |' % (c_00,c_01)
print '--|-------|-------|'
print 'S | %5d | %5d |' % (c_10,c_11)
trainfeats = negfeats[:4000] + posfeats[:4000]
testfeats = negfeats[4000:] + posfeats[4000:]
print("train on %d instances, test on %d instances" % (len(trainfeats), len(testfeats)))
classifier = NaiveBayesClassifier.train(trainfeats)
refsets = collections.defaultdict(set)
testsets = collections.defaultdict(set)
for i, (feats, label) in enumerate(testfeats):
refsets[label].add(i)
observed = classifier.classify(feats)
testsets[observed].add(i)
# cross validation 3-fold
feats = negfeats + posfeats
M = math.floor(len(feats) / 3)
result = []
for n in range(3):
val_set = feats[n * M :][:M]
train_set = feats[(n + 1) * M :] + feats[: n * M]
classifier = nltk.NaiveBayesClassifier.train(train_set)
result.append("{:.4f}".format(round(nltk.classify.accuracy(classifier, val_set) * 100, 4)))
print("cross_validation:", result)
print("pos precision:", precision(refsets["pos"], testsets["pos"]))
print("pos recall:", recall(refsets["pos"], testsets["pos"]))
print("pos F-measure:", f_measure(refsets["pos"], testsets["pos"]))
print("neg precision:", precision(refsets["neg"], testsets["neg"]))
print("neg recall:", recall(refsets["neg"], testsets["neg"]))
print("neg F-measure:", f_measure(refsets["neg"], testsets["neg"]))
classifier.show_most_informative_features()
def validate(self, validation_set):
if self.classifier is None:
raise Exception("self.classifier is None")
reference=defaultdict(set)
observed=defaultdict(set)
observed['neutral']=set()
for i, (tweet, label) in enumerate(validation_set):
reference[label].add(i)
observation=self.classify(tweet)
observed[observation].add(i)
acc=classify.accuracy(self.classifier, observed)
posp=precision(reference['positive'],observed['positive'])
posr=recall(reference['positive'], observed['positive'])
posf=f_measure(reference['positive'], observed['positive'])
negp=precision(reference['negative'],observed['negative'])
negr=recall(reference['negative'], observed['negative'])
negf=f_measure(reference['negative'], observed['negative'])
print "accuracy: %s" % acc
print "pos precision: %s" % posp
print "pos recall: %s" % posr
print "pos f-measure: %s" % posf
print "neg precision: %s" % negp
print "neg recall: %s" % negr
print "neg f-measure: %s" % negf
return (acc, posp, posr, posf, negp, negr, negf)