def exploreTaggedCorpora():
brown_learned_text = brown.words(categories='learned')
sorted(set(b for (a, b) in nltk.ibigrams(brown_learned_text) if a == 'often'))
brown_lrnd_tagged = brown.tagged_words(categories='learned', simplify_tags=True)
tags = [b[1] for (a, b) in nltk.ibigrams(brown_lrnd_tagged) if a[0] == 'often']
fd = nltk.FreqDist(tags)
fd.tabulate()
def process(sentence):
for (w1,t1), (w2,t2), (w3,t3) in nltk.trigrams(sentence):
if (t1.startswith('V') and t2 == 'TO' and t3.startswith('V')):
print w1, w2, w3
for tagged_sent in brown.tagged_sents():
process(tagged_sent)
brown_news_tagged = brown.tagged_words(categories='news', simplify_tags=True)
data = nltk.ConditionalFreqDist((word.lower(), tag)
for (word, tag) in brown_news_tagged)
for word in data.conditions():
if len(data[word]) > 3:
tags = data[word].keys()
print word, ' '.join(tags)
def exploreTaggedCorpora():
brown_learned_text = brown.words(categories="learned")
sorted(set(b for (a, b) in nltk.ibigrams(brown_learned_text) if a == "often"))
brown_lrnd_tagged = brown.tagged_words(categories="learned", simplify_tags=True)
tags = [b[1] for (a, b) in nltk.ibigrams(brown_lrnd_tagged) if a[0] == "often"]
fd = nltk.FreqDist(tags)
fd.tabulate()
def process(sentence):
for (w1, t1), (w2, t2), (w3, t3) in nltk.trigrams(sentence):
if t1.startswith("V") and t2 == "TO" and t3.startswith("V"):
print w1, w2, w3
for tagged_sent in brown.tagged_sents():
process(tagged_sent)
brown_news_tagged = brown.tagged_words(categories="news", simplify_tags=True)
data = nltk.ConditionalFreqDist((word.lower(), tag) for (word, tag) in brown_news_tagged)
for word in data.conditions():
if len(data[word]) > 3:
tags = data[word].keys()
print word, " ".join(tags)
def bgram_by_word(words, rel_word):
"""
Function for returning a bigram for a particular word from a tagged corpus
of words
"""
return list(
set(word2.lower() for (word1, word2) in nltk.ibigrams(words)
if word1 == rel_word))
def nextags(tagged, word):
"""
Add the tag of the next word to our list of tags.
"""
tags = []
for ((word1, tgram1), (word2, tgram2)) in nltk.ibigrams(tagged):
if word1 == word:
tags.append(tgram2)
return list(set(tags))
def nextags(tagged, word):
"""
Add the tag of the next word to our list of tags.
"""
tags = []
for ((word1, tgram1), (word2, tgram2)) in nltk.ibigrams(tagged):
if word1 == word:
tags.append(tgram2)
return list(set(tags))
def tokenize_and_ngram(text):
tokens = [x.lower() for x in twtokenize.word_tokenize(text)]
# Split into sublists using stopwords. This keeps us from
# generating n-grams from words that aren't actually next
# to each other. This step also removes the stopwords
tokens = list(splitlist(tokens, stopwords))
bgrams = [nltk.ibigrams(subtokens) for subtokens in tokens]
tgrams = [nltk.itrigrams(subtokens) for subtokens in tokens]
terms = list(chain(*(tokens + bgrams + tgrams)))
return terms
def exercise1():
print("Part a")
#Which nouns are more common in their plural form, rather than their singular form
#(Use the parts of speech tags in the corpus to identify plural versus singular nouns
# and use nltk.WordNetLemmatizer() to get the singular form of a noun from its plural form).
# List the five most frequent nouns that feature this property.
brown_words = brown.words()
brown_tags = brown.tagged_words()
tagdict = findtags(
'NNS', brown_tags) # a dictionary with a list of words have 'NNS' tag
lem = nltk.WordNetLemmatizer()
words = []
cf = nltk.FreqDist(brown_words)
#print brown_words[:50]
tag = 'NNS'
for plural in tagdict[tag]:
singular = lem.lemmatize(plural)
#print plural, singular
freq_sing = cf[singular]
freq_plur = cf[plural]
if freq_plur > freq_sing:
words.append(plural)
words.sort(key=lambda a: cf[a], reverse=True)
print tag, "5 plural nouns more common:", words[:
5] # last elements
#print cf['years'], cf['yaks']
print("Part b")
# List the 5 most frequent tags in order of decreasing frequency. What do the tags represent?
tags = [b[1] for (a, b) in nltk.ibigrams(brown_tags)]
fd = nltk.FreqDist(tags)
print fd.keys()[:10]
print fd.values()[:10]
i = 0
for i in range(0, 5):
print fd.keys()[i], fd.values()[i]
#print " 'NN' is Noun, 'AT' prepositions, 'IN' prepositions, 'JJ' adverb"
#for key in fd.keys():
#if key != '.' or key != ',':
#print key, fd.values()[counter]
#counter = counter + 1
#if counter > 5:
#break
print("The tags represent the decrease in frequency.")
print("Part c")
# Which three tags precede nouns tagged with the 'NN' tag most commonly? What do these three tags represent?
# Report your findings separately for the following categories of Brown corpus: humor, romance, government.
categories = ['humor', 'romance', 'government']
for category in categories:
#tagged_dict = findtags('NN', brown.tagged_words(categories=category))
category_tags = brown.tagged_words(categories=category)
tagList = [
b[1] for (a, b) in nltk.ibigrams(category_tags)
if b[1].startswith('N') and b[1] != 'N'
]
#print category, tagList[:20]
fd = nltk.FreqDist(tagList)
print category, ', '.join(fd.keys()[:3])
import nltk from nltk.corpus import brown # brown_learned_text = brown.words(categories='learned') # brown_sorted = sorted(set(b for (a, b) in nltk.ibigrams(brown_learned_text) if a == 'often')) brown_learned_text_tagged = brown.tagged_words(categories='learned', simplify_tags=True) ## b[0] is the word after a ## b[1] is part of speech of the word after a ## a[0] is, in this case, 'often' ## a[1] is, in this case, the part of speech of 'often' tags = [b[1] for (a, b) in nltk.ibigrams(brown_learned_text_tagged) if a[0] == 'often'] freq_dist = nltk.FreqDist(tags) freq_dist_tab = freq_dist.tabulate() print freq_dist_tab
def nextags(tagged, word):
tags = []
for ((w1, t1), (w2, t2)) in nltk.ibigrams(tagged):
if w1 == word:
tags.append(t2)
return list(set(tags))
def ibgram_by_word(words,rel_word): return list(set(word2.lower() for (word1, word2) in nltk.ibigrams(words) if word1 == rel_word))
training_data, test_data = text[:cut], text[cut:]
#sort words in a string by their length
words = 'I turned off the spedsdsd'.split()
wordlens = [(len(word),word) for word in words]
wordlens.sort()
' '.join(w for (_, w) in wordlens)
#parameters checking
assert isinstance(word, basestring), "argument must be a string"
#weird function bug on page 157
b is c
b == c
#Chapter 5
nltk.pos_tag(text)
#simplified POS tagset on page 183
sorted(set(b for (a,b) in nltk.ibigrams(brown_learned_text) if a == 'often'))
tags = [b[1] for (a, b) in nltk.ibigrams(brown_Irnd_tagged) if a[0] == 'often']
fd = ntlk.FreqDist(tags)
pos.keys()
pos.values()
pos = nltk.defaultdict(lambda: 'N')
sorted(counts.items(), key=itemgetter(1), reverse=True)
#inverting a dictionary
pos = {'colorless': 'ADJ', 'ideas': 'N', 'sleep': 'V'}
pos2 = dict((value, key) for (key, value) in pos.items())
#dictionary methods summary is on page 198
bigram_tagger = nltk.BigramTagger(train_sents)
bigram_tagger.tag(brown_sents[2007])
#tagging: default tagger, regex tagger, unigram tagger and n-gram tagger
#we can set backoff to combine taggers
import nltk
from nltk.corpus import brown
# brown_learned_text = brown.words(categories='learned')
# brown_sorted = sorted(set(b for (a, b) in nltk.ibigrams(brown_learned_text) if a == 'often'))
brown_learned_text_tagged = brown.tagged_words(categories='learned',
simplify_tags=True)
## b[0] is the word after a
## b[1] is part of speech of the word after a
## a[0] is, in this case, 'often'
## a[1] is, in this case, the part of speech of 'often'
tags = [
b[1] for (a, b) in nltk.ibigrams(brown_learned_text_tagged)
if a[0] == 'often'
]
freq_dist = nltk.FreqDist(tags)
freq_dist_tab = freq_dist.tabulate()
print freq_dist_tab
def bgram_by_word(words, rel_word):
"""
Function for returning a bigram for a particular word from a tagged corpus
of words
"""
return list(set(word2.lower() for (word1, word2) in nltk.ibigrams(words) if word1 == rel_word))
cfd2 = nltk.ConditionalFreqDist((tag, word) for (word, tag) in wsj)
cfd2['VN'].keys()
# pg. 187
def findtags(tag_prefix, tagged_text):
cfd = nltk.ConditionalFreqDist((tag, word) for (word, tag) in tagged_text if tag.startswith(tag_prefix))
return dict((tag, cfd[tag].keys()[:5]) for tag in cfd.conditions())
tagdict = findtags('NN', nltk.corpus.brown.tagged_words(categories='news'))
for tag in sorted(tagdict):
print tag, tagdict[tag]
from nltk.corpus import brown
brown_learned_text = brown.words(categories='learned')
sorted(set(b for (a, b) in nltk.ibigrams(brown_learned_text) if a == 'often'))
# pg. 188
brown_lrnd_tagged = brown.tagged_words(categories='learned', simplify_tags=True)
tags = [b[1] for (a, b) in nltk.ibigrams(brown_lrnd_tagged) if a[0] == 'often']
fd = nltk.FreqDist(tags)
fd.tabulate()
from nltk.corpus import brown
def process(sentence):
for (w1, t1), (w2,t2), (w3,t3) in nltk.trigrams(sentence):
if (t1.startswith('V') and t2 == 'TO' and t3.startswith('V')):
print w1, w2, w3
for tagged_sent in brown.tagged_sents():
# pg. 187
def findtags(tag_prefix, tagged_text):
cfd = nltk.ConditionalFreqDist((tag, word) for (word, tag) in tagged_text
if tag.startswith(tag_prefix))
return dict((tag, cfd[tag].keys()[:5]) for tag in cfd.conditions())
tagdict = findtags('NN', nltk.corpus.brown.tagged_words(categories='news'))
for tag in sorted(tagdict):
print tag, tagdict[tag]
from nltk.corpus import brown
brown_learned_text = brown.words(categories='learned')
sorted(set(b for (a, b) in nltk.ibigrams(brown_learned_text) if a == 'often'))
# pg. 188
brown_lrnd_tagged = brown.tagged_words(categories='learned',
simplify_tags=True)
tags = [b[1] for (a, b) in nltk.ibigrams(brown_lrnd_tagged) if a[0] == 'often']
fd = nltk.FreqDist(tags)
fd.tabulate()
from nltk.corpus import brown
def process(sentence):
for (w1, t1), (w2, t2), (w3, t3) in nltk.trigrams(sentence):
if (t1.startswith('V') and t2 == 'TO' and t3.startswith('V')):
word_tag_fd = nltk.FreqDist(wsj)
idx1 = wsj.index(("kicked", "VD"))
def findtags(tag_prefix, tagged_text):
cfd = nltk.ConditionalFreqDist((tag, word) for (word, tag) in tagged_text if tag.startswith(tag_prefix))
return dict((tag, cfd[tag].keys()[:5]) for tag in cfd.conditions())
tagdict = findtags("NN", nltk.corpus.brown.tagged_words(categories="news"))
for tag in sorted(tagdict):
print tag, tagdict[tag]
brown_learned_text = brown.words(categories="learned")
sorted(set(b for (a, b) in nltk.ibigrams(brown_learned_text) if a == "often"))
brown_lrnd_tagged = brown.tagged_words(categories="learned", simplify_tags=True)
tags = [b[1] for (a, b) in nltk.ibigrams(brown_lrnd_tagged) if a[0] == "often"]
fd = nltk.FreqDist(tags)
fd.tabulate()
def process(sentence):
for (w1, t1), (w2, t2), (w3, t3) in nltk.trigrams(sentence):
if t1.startswith("V") and t2 == "TO" and t3.startswith("V"):
print w1, w2, w3
for tagged_sent in brown.tagged_sents():
process(tagged_sent)
def bgram_by_word(words, rel_word):
return list(set(w2.lower() for (w1, w2) in nltk.ibigrams(words) if w1 == rel_word))
