def _handle_missing(df):
from pyspark.ml.feature import Imputer
from pyspark.sql import functions as F
# handle missing values
columns = list(
filter(lambda col: col not in ('class', 'weight', 'crime_pair'),
df.columns))
dtypes = dict(df.dtypes)
# for int columns
int_columns = list(
filter(lambda col: dtypes[col] not in ('float', 'double'), columns))
stats = df.agg(*(F.avg(c).alias(c) for c in int_columns))
fillers = {
k: round(v)
for k, v in stats.first().asDict().items() if v is not None
}
df = df.na.fill(fillers)
# for float columns
float_columns = list(
filter(lambda col: dtypes[col] in ('float', 'double'), columns))
print(float_columns)
imputer = Imputer(
inputCols=float_columns,
outputCols=["{}_imputed".format(c) for c in float_columns])
df = imputer.fit(df).transform(df)
df = df.drop(*float_columns)
return df
def cleanDraftData(postion):
'''
[X] need to fill in nulls for the Age with the AVG, or with the median of all the ages --> opted out for the medium
'''
unCleanData = spark.read.format("csv").option("header", "true").option(
"inferSchema", "true").load("./data/NflDraftData/draftData.csv")
# drop columns we don't need
unCleanData = unCleanData.select("Rnd", "Pick", "Player Name", "Pos",
'Age', 'College', 'Draft Year')
if (postion == "RB" or postion == "QB" or postion == "WR"):
unCleanData = unCleanData.where(unCleanData["Pos"] == postion)
else: # Retrun all of the skill offensive players (WR, RB, TE, QB, FB)
#drop lineman both offense and defense as well as defensive players and special teams
droppedPostions = [
'DE', 'DT', 'T', 'O', 'G', 'C', 'K', 'NT', 'DL', 'OL', 'LS', 'LB',
'DB', 'P', 'OLB', 'CB', 'S', 'ILB'
] # With only O players we are down to 2000 data pints
for postion in droppedPostions:
unCleanData = unCleanData.where(unCleanData["Pos"] != postion)
# Cast values to doubles
doubleCols = ['Age', 'Rnd', 'Pick', 'Draft Year']
for c in doubleCols:
unCleanData = unCleanData.withColumn(c,
unCleanData[c].cast(DoubleType()))
# Used to fill in Null values with the medium
imputer = Imputer(inputCols=["Age"], outputCols=["Age"])
cleanData = imputer.setStrategy("median").fit(unCleanData).transform(
unCleanData)
#cleanData.show()
return cleanData
def impute_missing(df, columns, out_cols, strategy='mean'):
"""
Imputes missing data from specified columns using the mean or median.
Parameters
----------
columns : List of columns to be analyze.
out_cols: List of output columns with missing values imputed.
strategy: String that specifies the way of computing missing data. Can be "mean" or "median"
return : Transformer object (DF with columns that has the imputed values).
"""
# Check if columns to be process are in dataframe
assert_cols_in_df(df, columns_provided=columns, columns_df=df.columns)
assert isinstance(columns, list), "Error: columns argument must be a list"
assert isinstance(out_cols,
list), "Error: out_cols argument must be a list"
# Check if columns argument a string datatype:
assert_type_str(df, strategy, "strategy")
assert (
strategy == "mean" or strategy == "median"
), "Error: strategy has to be 'mean' or 'median'. 'mean' is default"
imputer = Imputer(inputCols=columns, outputCols=out_cols)
model = imputer.setStrategy(strategy).fit(df)
df = model.transform(df)
return df
def imputeMonthlyIncome(df):
imputer = Imputer(inputCols=['MonthlyIncome'],
outputCols=['imputed_MonthlyIncome'],
strategy='median')
# Columns are required to either double or float by the Imputer...
df = df.withColumn(
'double_MonthlyIncome',
df.MonthlyIncome.cast(DoubleType())
).drop('MonthlyIncome') \
.withColumnRenamed('double_MonthlyIncome', 'MonthlyIncome')
df = imputer.fit(df).transform(df).drop('MonthlyIncome')
df = df.withColumnRenamed('imputed_MonthlyIncome', 'MonthlyIncome')
# Addressing MonthlyIncome of 0
incomeMedian = np.median(df.select('MonthlyIncome').collect())
# Apply income median if the MonthlyIncome is 0
df = df.withColumn(
'MonthlyIncome',
F.when((F.col('MonthlyIncome') == 1),
incomeMedian).otherwise(F.col('MonthlyIncome')))
return df
def _imputer_test_single(self):
data = self.spark.createDataFrame([(1.0, float("nan")),
(2.0, float("nan")),
(float("nan"), 3.0), (4.0, 4.0),
(5.0, 5.0)], ["a", "b"])
imputer = Imputer(inputCols=["a"], outputCols=["out_a"])
model = imputer.fit(data)
# the input name should match the inputCols above
model_onnx = convert_sparkml(model, 'Sparkml Imputer',
[('a', FloatTensorType([None, 1]))])
self.assertTrue(model_onnx is not None)
# run the model
predicted = model.transform(data)
expected = predicted.select("out_a").toPandas().values.astype(
numpy.float32)
data_np = data.toPandas().a.values.astype(numpy.float32)
data_np = data_np.reshape((-1, 1))
paths = save_data_models(data_np,
expected,
model,
model_onnx,
basename="SparkmlImputerSingle")
onnx_model_path = paths[-1]
output, output_shapes = run_onnx_model(['out_a'], data_np,
onnx_model_path)
compare_results(expected, output, decimal=5)
def preprocess(df):
cont_col = ['_c{0}'.format(i) for i in range(0, 14)]
for i in cont_col:
df = df.withColumn(i, df[i].cast("float"))
# Continuous columns fill null with mean
imputer=Imputer(inputCols=cont_col,outputCols=cont_col).setStrategy('mean')
return imputer.fit(df).transform(df)
def imputaciones(VarLimpias):
C = [i[0] for i in VarLimpias.dtypes if 'string' in i[1]]
I = [i[0] for i in VarLimpias.dtypes if 'int' in i[1]]
for f in I:
VarLimpias = VarLimpias.withColumn(f, VarLimpias[f].cast(DoubleType()))
imputer = Imputer(inputCols=[c for c in VarLimpias.columns if c not in C],
outputCols=[c for c in VarLimpias.columns if c not in C])
Pba = imputer.fit(VarLimpias)
return Pba.transform(VarLimpias)
def imputation(self):
C=[i[0] for i in self.data.dtypes if 'string' in i[1]]
I=[i[0] for i in self.data.dtypes if 'int' in i[1]]
for f in I: self.data = self.data.withColumn(f, self.data[f].cast(DoubleType()))
imputer = Imputer(
inputCols= [c for c in self.data.columns if c not in C],
outputCols=[c for c in self.data.columns if c not in C])
Pba=imputer.fit(self.data)
return Pba.transform(self.data)
def na_imputer(self, strategy, out_columns="*", na=None, columns="*"):
"""
replace missing value with mean or median according to users' choice
user can also customize the definition of missing value, e.g. 999
the default missing value is 'nan' or null
the default setting of out_columns is just columns, so the original columns will be overrided if not specially defined
"""
#check columns
if columns == "*":
columns = self._df.schema.names
elif isinstance(columns, str):
columns = [columns]
else:
assert isinstance(
columns,
list), "Error: columns argument must be a string or a list!"
if out_columns == "*":
out_columns = self._df.schema.names
#check output columns
if isinstance(out_columns, str):
out_columns = [out_columns]
else:
assert isinstance(
out_columns, list
), "Error: output columns argument must be a string or a list!"
#check input and output columns have consistent lengths
assert len(columns) == len(
out_columns
), "Error: inconsistent lengths for argument of columns list and output columns list"
#check strategy argument
assert (strategy == "mean" or strategy
== "median"), "Error: strategy can only be 'mean' or 'median'."
#firstly convert the type in input columns to FloatType for Imputer
for col in columns:
self._df = self._df.withColumn(col,
self._df[col].cast(FloatType()))
#fit the model
imputer = Imputer(inputCols=columns, outputCols=out_columns)
if na is None:
model = imputer.setStrategy(strategy).fit(self._df)
else:
model = imputer.setStrategy(strategy).setMissingValue(na).fit(
self._df)
self._df = model.transform(self._df)
return self._df
def imputer_continuous_features(df, data_types_map):
continuous_features = list(
set(data_types_map['DoubleType']) - set(['DEP_DEL15']))
continuous_features_imputed = [
var + "_imputed" for var in continuous_features
]
imputer = Imputer(inputCols=continuous_features,
outputCols=continuous_features_imputed)
tmp = imputer.fit(df).transform(df)
get_missing_info(tmp)
return [imputer]
def imputers(dataframe):
inputCols = []
outputCols = []
for i in range(1,14):
feature = 'I-'+str(i)
dataframe = dataframe.withColumn(feature, dataframe[feature].cast(DoubleType()))
inputCols.append(feature)
outputCols.append(feature)
imputer = Imputer(strategy="mean",
inputCols=inputCols,
outputCols=outputCols)
return imputer.fit(dataframe).transform(dataframe)
def fill_na_numerical(self,data,columns):
'''
FILL NULL VALUES FOR NUMERICAL DATA
args:
1.data: <SPARK DATAFRAME> actual spark dataframe
2.columns: <LIST> of numerical columns we want to Impute
return: <SPARK DATAFRAME>Imputed spark dataframe
'''
columns=list(columns)
imputer=Imputer(inputCols=columns,outputCols=['imputed_'+str(col) for col in columns])
dataCopy=imputer.fit(data).transform(data)
return dataCopy
def fill_na_numerical(self, data, columns):
'''
Purpose: Fill null values for numerical data
Inputs : Data(spark dataframe), column(numerical columns)
Output : Imputed spark dataframe
'''
columns = list(columns)
imputer = Imputer(
inputCols=columns,
outputCols=['imputed_' + str(col) for col in columns])
dataCopy = imputer.fit(data).transform(data)
return dataCopy
def imputer_usecase():
"""
用于计算数据集中的缺失值,使用指定的策略进行数据填充，
strategy指定数据填充策略,
"""
spark = getSparkSession()
df = spark.createDataFrame([(1.0, float("nan")), (2.0, float("nan")),
(float("nan"), 3.0), (4.0, 4.0), (5.0, 5.0)],
["a", "b"])
imputer = Imputer(inputCols=["a", "b"], outputCols=["out_a", "out_b"])
model = imputer.fit(df)
model.transform(df).show()
def preprocessing(self):
model = GBTRegressor(labelCol="bicycle_rentals")
cols = [
"part_time", "holiday", "week_days", "weather_description_mf",
"month"
]
imputer = Imputer(inputCols=["humidity", "pressure"],
outputCols=["humidity_input", "pressure_input"])
indexers = [
StringIndexer(inputCol=col, outputCol="{0}_indexed".format(col))
for col in cols
]
assembler = VectorAssembler(inputCols=[
"part_time_indexed", "holiday_indexed", "month_indexed",
"week_days_indexed", "weather_description_mf_indexed",
"humidity_input", "pressure_input", "temperature", "wind_speed",
"from_station_id", "mean_dpcapacity_start", "mean_dpcapacity_end",
"sum_subscriber", "sum_customer"
],
outputCol="features")
pipeline = Pipeline(stages=[imputer] + indexers + [assembler] +
[model])
return pipeline
def prepocess_data(df):
# Preprocessing the data
# Dimension reduction
cols_reduce = [
'Date', 'Time', 'Sub_metering_1', 'Sub_metering_2', 'Sub_metering_3'
]
df = df.drop(*cols_reduce)
# Fixing missing values (dataset uses ? as NaN for missing values)
imputer = Imputer(inputCols=df.columns, outputCols=df.columns)
imputer.setStrategy("mean")
df = imputer.fit(df).transform(df)
# Print the column name and datatype
print(df.dtypes)
return df
def get_ml1_pipeline():
stages = []
imputer = Imputer(inputCols=ML1_NUMERICAL_COLUMNS , outputCols=ML1_NUMERICAL_COLUMNS )
stages.append(imputer)
ohe_input_cols = []
ohe_output_cols = []
for categorical_column in ML1_CATEGORICAL_COLUMNS:
str_indexer = StringIndexer(inputCol=categorical_column, outputCol=categorical_column + "_index", handleInvalid='keep')
ohe_input_cols.append(str_indexer.getOutputCol())
ohe_output_cols.append(categorical_column + "_class_vec")
stages.append(str_indexer)
encoder = OneHotEncoderEstimator(inputCols=ohe_input_cols, outputCols=ohe_output_cols, handleInvalid="error", dropLast=False)
stages.append(encoder)
numerical_vector_assembler = VectorAssembler(inputCols=ML1_NUMERICAL_COLUMNS , outputCol="numerial_cols_vec", handleInvalid="keep")
scaler = MinMaxScaler(inputCol="numerial_cols_vec", outputCol= "scaled_numerical_cols")
stages.append(numerical_vector_assembler)
stages.append(scaler)
label_str_indexer = StringIndexer(inputCol="result", outputCol="label", handleInvalid="keep")
stages.append(label_str_indexer)
assembler_input = encoder.getOutputCols() + [scaler.getOutputCol()]
assembler = VectorAssembler(inputCols= assembler_input, outputCol="features", handleInvalid="skip")
stages.append(assembler)
pipeline = Pipeline(stages = stages)
return pipeline
def _fit_crossvalidator(train, features, target):
"""
Helper function that fits a CrossValidator model to predict a binary label
`target` on the passed-in training DataFrame using the columns in `features`
:param: train: Spark DataFrame containing training data
:param: features: List of strings containing column names to use as features from `train`
:param: target: String name of binary target column of `train` to predict
"""
train = train.select(features + [target])
model_matrix_stages = [
Imputer(inputCols=features, outputCols=features),
VectorAssembler(inputCols=features, outputCol="features"),
StringIndexer(inputCol="bad_loan", outputCol="label")
]
lr = LogisticRegression(maxIter=10,
elasticNetParam=0.5,
featuresCol="features")
pipeline = Pipeline(stages=model_matrix_stages + [lr])
paramGrid = ParamGridBuilder().addGrid(lr.regParam, [0.1, 0.01]).build()
crossval = CrossValidator(estimator=pipeline,
estimatorParamMaps=paramGrid,
evaluator=BinaryClassificationEvaluator(),
numFolds=5)
with mlflow.start_run():
mlflow.log_param("data_version", version_to_load)
mlflow.log_param("data_path", DELTA_TABLE_DEFAULT_PATH)
cvModel = crossval.fit(train)
return cvModel.bestModel
def handle_missing(self, non_feature_col=["ID", "TIME_SPAN"]):
import pyspark
if type(self) == data_run_experiment:
raise NotImplementedError(
"Method need to be called in sub-class but currently called in base class"
)
try:
ret_data_frame = self.spark.read.parquet(self.temp_missing_drop)
self.logger.info(self.temp_missing_drop)
return ret_data_frame
except pyspark.sql.utils.AnalysisException as ex:
template = "An exception of type {0} occurred. Arguments:\n{1!r}"
message = template.format(type(ex).__name__, ex.args)
self.logger.info(message)
self.logger.info("PROCESS")
#impute only. aggregation will be done after adding demographics
cur_df = self.spark.read.parquet(self.out_file_name)
cur_cols = cur_df.columns
categorical_cols = list()
numerical_cols = list()
for i in non_feature_col:
cur_cols.remove(i)
for i in cur_cols:
if i.find("C_") == 0:
categorical_cols.append(i)
else:
numerical_cols.append(i)
cur_df = cur_df.fillna(
0, subset=categorical_cols).repartition(400).checkpoint()
self.logger.info(cur_df.count())
from pyspark.ml.feature import Imputer
imputedCols = ["imp_{0}".format(x) for x in numerical_cols]
imputer = Imputer(inputCols=numerical_cols,
outputCols=imputedCols).setStrategy("mean")
imputer_model = imputer.fit(cur_df)
ret_data_frame = imputer_model.transform(cur_df)
ret_data_frame.select(non_feature_col + imputedCols +
categorical_cols).show()
ret_data_frame.select(non_feature_col + imputedCols +
categorical_cols).write.save(
self.temp_missing_drop)
ret_data_frame = self.spark.read.parquet(self.temp_missing_drop)
return ret_data_frame
def _fit_crossvalidator(train, features, target, version):
"""
Helper function that fits a CrossValidator model to predict a binary label
`target` on the passed-in training DataFrame using the columns in `features`
:param: train: Spark DataFrame containing training data
:param: features: List of strings containing column names to use as features from `train`
:param: target: String name of binary target column of `train` to predict
"""
train = train.select(features + [target])
model_matrix_stages = [
Imputer(inputCols=features, outputCols=features),
VectorAssembler(inputCols=features, outputCol="features"),
StringIndexer(inputCol="bad_loan", outputCol="label")
]
lr = LogisticRegression(maxIter=10,
elasticNetParam=0.5,
featuresCol="features")
pipeline = Pipeline(stages=model_matrix_stages + [lr])
paramGrid = ParamGridBuilder().addGrid(lr.regParam, [0.1, 0.01]).build()
crossval = CrossValidator(estimator=pipeline,
estimatorParamMaps=paramGrid,
evaluator=BinaryClassificationEvaluator(),
numFolds=5)
import matplotlib.pyplot as plt
from mlflow import spark as mlflow_spark
from mlflow import sklearn as mlflow_sk
mlflow.start_run()
cvModel = crossval.fit(train)
best_model = cvModel.bestModel
roc = best_model.stages[len(best_model.stages) - 1].summary.roc.toPandas()
fig1 = plt.figure()
fig1.clf()
plt.clf()
plt.plot(roc['FPR'], roc['TPR'])
plt.ylabel('False Positive Rate')
plt.xlabel('True Positive Rate')
plt.title('ROC Curve')
fig1.savefig("roc.png")
mlflow.log_artifact("roc.png")
fig1.clf()
plt.clf()
lr_summary = best_model.stages[len(best_model.stages) - 1].summary
mlflow.log_metric("accuracy", lr_summary.accuracy)
mlflow.log_metric("weightedFalsePositiveRate",
lr_summary.weightedFalsePositiveRate)
mlflow.log_metric("weightedFalsePositiveRate",
lr_summary.weightedFalsePositiveRate)
mlflow.log_metric("weightedFMeasure", lr_summary.weightedFMeasure())
mlflow.log_metric("weightedPrecision", lr_summary.weightedPrecision)
mlflow.log_metric("weightedRecall", lr_summary.weightedRecall)
mlflow_spark.log_model(best_model, "loan-classifier-mllib")
mlflow.end_run()
return best_model
def imputer_mean(df):
weather_numeric_with_nulls = [
'origin_WND_speed_rate', 'origin_CIG_ceiling_height',
'origin_VIS_distance', 'origin_TMP_air_temperature',
'origin_DEW_dew_point_temp', 'dest_WND_speed_rate',
'dest_CIG_ceiling_height', 'dest_VIS_distance',
'dest_TMP_air_temperature', 'dest_DEW_dew_point_temp',
'origin_aa1_rain_depth', 'dest_aa1_rain_depth',
'origin_aj1_snow_depth', 'dest_aj1_snow_depth'
]
imputer = Imputer(inputCols=weather_numeric_with_nulls,
outputCols=weather_numeric_with_nulls)
model = imputer.fit(filter_to_train(df))
df = model.transform(df)
return df
def impute(input_cols, output_cols, strategy="mean"):
"""
Imputes missing data from specified columns using the mean or median.
:param input_cols: List of columns to be analyze.
:param output_cols: List of output columns with missing values imputed.
:param strategy: String that specifies the way of computing missing data. Can be "mean" or "median"
:return: Dataframe object (DF with columns that has the imputed values).
"""
input_cols = parse_columns(self, input_cols)
output_cols = val_to_list(output_cols)
imputer = Imputer(inputCols=input_cols, outputCols=output_cols)
df = self
model = imputer.setStrategy(strategy).fit(df)
df = model.transform(df)
return df
def preprocessing(self, trainDF, validDF, testDF):
"""
Data preprocessing steps involving the following transformations:
1. One-Hot encoding of categorical variables
2. Imputation of missing values in numerical variables
3. Standardization of numerical variables
Parameters
-----------
trainDF: training data set
validDF: test data set
testDF: test data set
Returns
-----------
Transformed training and test data sets with the assembler vector
"""
# Extract numerical and categorical column names
cat_cols = [field for (field, dataType) in trainDF.dtypes if dataType == "string"]
num_cols = [field for (field, dataType) in trainDF.dtypes if ((dataType == "double") & \
(field != self.label_col))]
# Create output columns
index_output_cols = [x + "Index" for x in cat_cols]
ohe_output_cols = [x + "OHE" for x in cat_cols]
# num_output_cols = [x + "scaled" for x in num_cols]
# strinf indexer for categorical variables
s_indexer = StringIndexer(inputCols = cat_cols, outputCols = index_output_cols,
handleInvalid="skip")
# One-hot code categorical columns
cat_encoder = OneHotEncoder(inputCols = index_output_cols, outputCols = ohe_output_cols)
# Impute missing values in numerical columns
num_imputer = Imputer(inputCols = num_cols, outputCols = num_cols)
# Vector assembler
assembler_inputs = ohe_output_cols + num_cols
assembler = VectorAssembler(inputCols = assembler_inputs, outputCol = "unscaled_features")
# Features scaling using StandardScaler
scaler = StandardScaler(inputCol = assembler.getOutputCol(), outputCol = "features")
# Create pipeline
stages = [s_indexer, cat_encoder, num_imputer, assembler, scaler]
pipeline = Pipeline(stages = stages)
pipelineModel = pipeline.fit(trainDF)
# Preprocess training and test data
trainDF_scaled = pipelineModel.transform(trainDF)
validDF_scaled = pipelineModel.transform(validDF)
testDF_scaled = pipelineModel.transform(testDF)
return assembler, trainDF_scaled, validDF_scaled, testDF_scaled
def missing_val_imput(self):
check = self.input.select(*(sum(col(c).isNull().cast("int")).alias(c)
for c in self.input.columns))
check.show()
print("||| Above table shows missing values accross columns |||")
check_pd = self.input.toPandas()
val = check_pd.isnull().any().any()
if val == True:
imputer = Imputer(
inputCols=self.input.columns,
outputCols=["{}".format(c) for c in self.input.columns])
cleaned_input = imputer.fit(self.input).transform(self.input)
print("Missing values replaced with mean accross columns")
print("Returning cleaned data")
return cleaned_input
else:
print("No missing value found")
return self.input
def replace_missings(self, test=False):
"""
Replace missing values with a default value
"""
for col in list(self.config_dict.keys()):
# check if the replace missing transformation needs to be applied
if self.config_dict[col]["replace_missings"]["apply"]:
imputer = Imputer(
inputCols=[col],
outputCols=[
"{}_replace_missings".format(col)
]).setMissingValue(
self.config_dict[col]["replace_missings"]["value"])
if test:
self.test_data = imputer.fit(self.test_data).transform(
self.test_data)
else:
self.train_data = imputer.fit(self.train_data).transform(
self.train_data)
def imputeNumeric(numeric_DF):
'''
takes a spark df with continuous numeric columns
outputs a spark df where all null values are replaced with the column average
the first column, which is the outcome values, are preserved
'''
outputColumns=["{}".format(c) for c in numeric_DF.columns[1:11]]
catColumns = ["{}".format(c) for c in numeric_DF.columns[11:]]
imputer = Imputer(
inputCols=numeric_DF.columns[1:11],
outputCols=["{}".format(c) for c in numeric_DF.columns[1:11]]
)
model = imputer.fit(numeric_DF)
imputedDF = model.transform(numeric_DF).select(['_1']+outputColumns+catColumns)
return imputedDF
def impute(self):
from pyspark.ml.feature import Imputer
df = self.session.createDataFrame([(1.0, float("nan")),
(2.0, float("nan")),
(float("nan"), 3.0), (4.0, 4.0),
(5.0, 5.0)], ["a", "b"])
# 默认采用平均值进行填充
imputer = Imputer(inputCols=["a", "b"], outputCols=["out_a", "out_b"])
model = imputer.fit(df)
model.transform(df).show()
# 我们也可以设置为中位数，以及判定哪些是缺失值
# null 则自动被认为缺失值
imputer = Imputer(inputCols=["a", "b"],
outputCols=["out_a", "out_b"],
strategy="median",
missingValue=float("nan"))
model = imputer.fit(df)
model.transform(df).show()
## fit过程一般我们认为是一个学习的过程，我们也可以吧这个过程保留下来
## 遗憾的是，我们暂时没有办法变更参数
model.write().overwrite().save("/tmp/wow")
model = ImputerModel.read().load("/tmp/wow")
model.transform(df).show()
def main(self, sc, *args):
""" For each input files, i.e. train and test 'initiated, apply the same set of transformatons
"""
sqlContext = SQLContext(sc)
# For each key in the output dictionary of the Initiate task, i.e. train and test
for inputFile in Initiate(self.input_file, self.output_path).output():
df = sqlContext.read.csv(Initiate(
self.input_file, self.output_path).output()[inputFile].path,
sep=",",
header=True,
inferSchema=True)
# Select final list of features
list_features = ["Age", "Sex_indexed", "Fare", "Survived"]
df = df.select(*list_features)
# Replace missing values
cols_missing = ["Age"]
for col in cols_missing:
imputer = Imputer(inputCols=[col],
outputCols=[
"{}_replace_missings".format(col)
]).setMissingValue(26.0)
df = imputer.fit(df).transform(df)
# Discretize
cols_disc = {
"Age_replace_missings":
[-math.inf, 0.83, 21.0, 26.0, 33.0, 71.0, math.inf],
"Fare": [-math.inf, 7.225, 8.122, 26.0, 83.475, math.inf],
}
for col in cols_disc:
bucketizer = Bucketizer(splits=cols_disc[col],
inputCol=col,
outputCol="{}_discretized".format(col))
df = bucketizer.transform(df)
df.write.csv(self.output()[inputFile].path, header=True)
def impute(columns, strategy="mean"):
"""
Imputes missing data from specified columns using the mean or median.
:param columns: List of columns to be analyze.
:param strategy: String that specifies the way of computing missing data. Can be "mean" or "median"
:return: Dataframe object (DF with columns that has the imputed values).
"""
columns = parse_columns(self, columns, filter_by_column_dtypes=PYSPARK_NUMERIC_TYPES)
df = self
output_cols = []
for col_name in columns:
# Imputer require not only numeric but float or double
df = df.cols.cast(col_name, "float")
output_cols.append(col_name + IMPUTE_SUFFIX)
imputer = Imputer(inputCols=columns, outputCols=output_cols)
model = imputer.setStrategy(strategy).fit(df)
df = model.transform(df)
return df
def imputer(features_name, strategy="mean", missing_value=None, footer="_imputer"):
"""
Spark experiment method
Args:
features_name:
strategy:
missing_value:
footer:
Returns:
"""
output_names = [name+footer for name in features_name]
imputer = Imputer() \
.setInputCols(features_name) \
.setOutputCols(output_names)\
.setStrategy(strategy)
if missing_value:
imputer.setMissingValue(missing_value)
return imputer
Run with:
bin/spark-submit examples/src/main/python/ml/imputer_example.py
"""
# $example on$
from pyspark.ml.feature import Imputer
# $example off$
from pyspark.sql import SparkSession
if __name__ == "__main__":
spark = SparkSession\
.builder\
.appName("ImputerExample")\
.getOrCreate()
# $example on$
df = spark.createDataFrame([
(1.0, float("nan")),
(2.0, float("nan")),
(float("nan"), 3.0),
(4.0, 4.0),
(5.0, 5.0)
], ["a", "b"])
imputer = Imputer(inputCols=["a", "b"], outputCols=["out_a", "out_b"])
model = imputer.fit(df)
model.transform(df).show()
# $example off$
spark.stop()
