Python feature.StringIndexer類代碼示例

def main(sc, spark):
    # Load and vectorize the corpus
    corpus = load_corpus(sc, spark)
    vector = make_vectorizer().fit(corpus)

    # Index the labels of the classification
    labelIndex = StringIndexer(inputCol="label", outputCol="indexedLabel")
    labelIndex = labelIndex.fit(corpus)

    # Split the data into training and test sets
    training, test = corpus.randomSplit([0.8, 0.2])

    # Create the classifier
    clf = LogisticRegression(
        maxIter=10, regParam=0.3, elasticNetParam=0.8,
        family="multinomial", labelCol="indexedLabel", featuresCol="tfidf")

    # Create the model
    model = Pipeline(stages=[
        vector, labelIndex, clf
    ]).fit(training)

    # Make predictions
    predictions = model.transform(test)
    predictions.select("prediction", "indexedLabel", "tfidf").show(5)

    # Select (prediction, true label) and compute test error
    evaluator = MulticlassClassificationEvaluator(
        labelCol="indexedLabel", predictionCol="prediction", metricName="accuracy")
    accuracy = evaluator.evaluate(predictions)
    print("Test Error = %g" % (1.0 - accuracy))

    gbtModel = model.stages[2]
    print(gbtModel)  # summary only

def testClassification(data):
    # Train a GradientBoostedTrees model.

    stringIndexer = StringIndexer(inputCol="label", outputCol="indexLabel")
    si_model = stringIndexer.fit(data)
    td = si_model.transform(data)

    rf = RandomForestClassifier(numTrees=5, maxDepth=4, labelCol="indexLabel",seed=13)

    trainData,testData = td.randomSplit([0.8,0.2],13)

    predictionDF = rf.fit(trainData).transform(testData)

    selected = predictionDF\
        .select('label','indexLabel','prediction','rawPrediction','probability')
    for row in selected.collect():
        print row

    scoresAndLabels = predictionDF\
       .map(lambda x: (float(x.probability.toArray()[1]), x.indexLabel))
    for sl in scoresAndLabels.collect():
        print sl
    evaluator = BinaryClassificationEvaluator(labelCol='indexLabel',metricName='areaUnderROC')
    metric = evaluator.evaluate(selected)
    print metric

def train_random_forest(df):
    stringIndexer = StringIndexer(inputCol="label", outputCol="indexed")
    si_model = stringIndexer.fit(df)
    td = si_model.transform(df)
    rf = RandomForestClassifier(numTrees=3, maxDepth=2, labelCol="indexed",
                                seed=int(random.random()))
    return rf, rf.fit(td)

def build_decisionTree(path):

    df = load_data(path)
    avg_age=find_avg_age(df)
    df = data_preparation(df, avg_age)

    df = df.drop('Cabin')
    df = df.drop('Ticket')
    df = df.drop('Name')

    stringIndexer = StringIndexer(inputCol="Survived", outputCol="indexed")
    si_model = stringIndexer.fit(df)
    df = si_model.transform(df)
    df.show(truncate=False)

    dt = DecisionTreeClassifier(labelCol='indexed')
    grid = ParamGridBuilder().addGrid(dt.maxDepth, [1,2,3,5,6,8,10]).build()

    evaluator = BinaryClassificationEvaluator()
    cv = CrossValidator(estimator=dt, estimatorParamMaps=grid, evaluator=evaluator)
    cvModel = cv.fit(df)

    prediction = cvModel.transform(df)
    prediction.show(truncate=False)

    print "classification evaluation :" , evaluator.evaluate(prediction)

    return cvModel,avg_age

def build_randomForest(path):
    df = load_data(path)
    avg_age=find_avg_age(df)
    df = data_preparation(df, avg_age)

    df = df.drop('Cabin')
    df = df.drop('Ticket')
    df = df.drop('Name')

    stringIndexer = StringIndexer(inputCol="Survived", outputCol="indexed")
    si_model = stringIndexer.fit(df)
    df = si_model.transform(df)
    df.show()

    rdf = RandomForestClassifier(labelCol='indexed')
    grid = ParamGridBuilder().addGrid(rdf.maxDepth, [1,2,3,5,6,8,10])\
                            .addGrid(rdf.numTrees,[1,5,10,30,50,100,200]).build()

    evaluator = BinaryClassificationEvaluator()
    cv = CrossValidator(estimator=rdf, estimatorParamMaps=grid, evaluator=evaluator)
    cvModel = rdf.fit(df)

    prediction = cvModel.transform(df)
    prediction.show()

    print "classification evaluation :" , evaluator.evaluate(prediction)

    return cvModel,avg_age

def mapClickCategoricalFeatures():
		

	indexed = ""

	df = getDataFrame(CLICKS_HDPFILEPATH)
	
	df.persist(StorageLevel.DISK_ONLY)

	print df.columns
	
	#select columns to be mapped
	click_cols = ["C2", "C3", "C4", "C5", "C7", "C8"]

	for col in click_cols:

		if(indexed == ""):	
			indexed = df
	
		print indexed
		outcol = col+"Index"
		indexer = StringIndexer(inputCol=col, outputCol=outcol)
		indexed = indexer.fit(indexed).transform(indexed)

	indexed.show()

	indexed.persist(StorageLevel.DISK_ONLY)

	#indexed.select('C0', 'C1', 'C2Index', 'C3Index', 'C4Index', 'C5Index', 'C6', 'C7Index', 'C8Index').write.format('com.databricks.spark.csv').save(PATH+"extraction/clicks1.csv")


	indexed.select('C0', 'C1', 'C2Index', 'C3Index', 'C4Index', 'C5Index', 'C6', 'C7Index', 'C8Index').write.format('com.databricks.spark.csv').save(HADOOPDIR+"data/click_fraud/extraction/clicks_23feb12.csv")

def mapPublisherCategoricalFeatures():
	
	indexed = ""

	df = getDataFrame(PUBLISHERS_HDPFILEPATH)

	df.persist(StorageLevel.DISK_ONLY)

	print df.columns
	
	publisher_cols = ["C0", "C1", "C2", "C3"]
	
	for col in publisher_cols:

		if(indexed == ""):	
			indexed = df

		print indexed
		outcol = col+"Index"
		#stringindexer maps each value in inout colun into a double indexed value and creates a new column in dataframe
		indexer = StringIndexer(inputCol=col, outputCol=outcol)
		#fit and transform the columns using indexer		
		indexed = indexer.fit(indexed).transform(indexed)

	indexed.show()

	indexed.persist(StorageLevel.DISK_ONLY)

	indexed.select('C0Index', 'C1Index', 'C2Index', "C3Index").write.format('com.databricks.spark.csv').save(HADOOPDIR+"data/click_fraud/extraction/publishers_23feb12.csv")

def run(start1, end1, start2, end2, df, sc, sql_context, is_pred):
    lp_data= get_labeled_points(start1, end2, df, sc, sql_context)
    print lp_data.count()

    labelIndexer = StringIndexer(inputCol="label", outputCol="indexedLabel").fit(lp_data)
    td = labelIndexer.transform(lp_data)
    label2index = {}
    for each in  sorted(set([(i[0], i[1]) for i in td.select(td.label, td.indexedLabel).distinct().collect()]),
                key=lambda x: x[0]):
        label2index[int(each[0])] = int(each[1])
    print label2index

    featureIndexer = \
        VectorIndexer(inputCol="features", outputCol="indexedFeatures", maxCategories=4).fit(lp_data)

    rf = get_model()

    pipeline = Pipeline(stages=[labelIndexer, featureIndexer, rf])

    lp_train = lp_data.filter(lp_data.date3<end1).filter(lp_data.is_labeled == 1)
    model = pipeline.fit(lp_train)
    lp_check = lp_data.filter(lp_data.date2>start2)
    predictions = model.transform(lp_check)
    predictions = val(predictions, label2index, sql_context)

    if is_pred:
        predictions = predictions.filter(predictions.is_labeled ==0).filter(predictions.date2 == get_cur()).sort(predictions.prob.desc())
        dfToTableWithPar(sql_context, predictions, "predictions", get_cur())
        for each in predictions.take(10):
            print each

def label(df, column):
    """
    Create a labeled column.
    """
    indexer = StringIndexer(inputCol=column, outputCol=column+'_label')
    df = indexer.fit(df).transform(df)
    return df

def indexStringColumns(df, cols):
    #variable newdf will be updated several times
    newdata = df
    for c in cols:
        si = StringIndexer(inputCol=c, outputCol=c+"-x")
        sm = si.fit(newdata)
        newdata = sm.transform(newdata).drop(c)
        newdata = newdata.withColumnRenamed(c+"-x", c)
    return newdata

def events(df,column_name):
    i = column_name+"I"
    v = column_name+"V"
    stringIndexer = StringIndexer(inputCol=column_name, outputCol=i)
    model = stringIndexer.fit(df)
    indexed = model.transform(df)
    encoder = OneHotEncoder(inputCol=i, outputCol=v)
    encoded = encoder.transform(indexed)
    return encoded

def indexStringColumns(df, cols):
    from pyspark.ml.feature import StringIndexer
    #variable newdf will be updated several times
    newdf = df
    for c in cols:
        si = StringIndexer(inputCol=c, outputCol=c+"-num")
        sm = si.fit(newdf)
        newdf = sm.transform(newdf).drop(c)
        newdf = newdf.withColumnRenamed(c+"-num", c)
    return newdf

    def oneHotEncoding(self, df, input_col):
        stringInd = StringIndexer(inputCol=input_col, outputCol="indexed")
        model = stringInd.fit(df)
        td = model.transform(df)
        encoder = OneHotEncoder(inputCol="indexed", outputCol="features", dropLast=False)
        final_encoding = encoder.transform(td).select(df.id, 'features').cache()
        
        conv_udf = udf(lambda line: Vectors.dense(line).tolist())
        final_encoding = final_encoding.select(df.id,conv_udf(final_encoding.features).alias("num_"+input_col)).cache()

        return final_encoding

    def test_string_indexer_handle_invalid(self):
        df = self.spark.createDataFrame([
            (0, "a"),
            (1, "d"),
            (2, None)], ["id", "label"])

        si1 = StringIndexer(inputCol="label", outputCol="indexed", handleInvalid="keep",
                            stringOrderType="alphabetAsc")
        model1 = si1.fit(df)
        td1 = model1.transform(df)
        actual1 = td1.select("id", "indexed").collect()
        expected1 = [Row(id=0, indexed=0.0), Row(id=1, indexed=1.0), Row(id=2, indexed=2.0)]
        self.assertEqual(actual1, expected1)

        si2 = si1.setHandleInvalid("skip")
        model2 = si2.fit(df)
        td2 = model2.transform(df)
        actual2 = td2.select("id", "indexed").collect()
        expected2 = [Row(id=0, indexed=0.0), Row(id=1, indexed=1.0)]
        self.assertEqual(actual2, expected2)

rdd = labeledRdd.map(lambda doc: (cleanLower(doc[0]), doc[1]))

print "Text is cleaned"

sqlContext = SQLContext(sc)
df = sqlContext.createDataFrame(rdd, ["review", "label"])
dfTrain, dfTest = df.randomSplit([0.8, 0.2])

print "Random split is done"

tokenizerNoSw = tr.NLTKWordPunctTokenizer(
    inputCol="review", outputCol="wordsNoSw", stopwords=set(nltk.corpus.stopwords.words("english"))
)
hashing_tf = HashingTF(inputCol=tokenizerNoSw.getOutputCol(), outputCol="reviews_tf")
idf = IDF(inputCol=hashing_tf.getOutputCol(), outputCol="reviews_tfidf")
string_indexer = StringIndexer(inputCol="label", outputCol="target_indexed")
dt = DecisionTreeClassifier(featuresCol=idf.getOutputCol(), labelCol=string_indexer.getOutputCol(), maxDepth=10)

pipeline = Pipeline(stages=[tokenizerNoSw, hashing_tf, idf, string_indexer, dt])


# ****************************************************************
# *********************CROSS VALIDATION: 80%/20%******************
# *******************Model: DecisionTreeClassifier*****************
# *****************************************************************

evaluator = MulticlassClassificationEvaluator(
    predictionCol="prediction", labelCol="target_indexed", metricName="precision"
)

grid = ParamGridBuilder().baseOn([evaluator.metricName, "precision"]).addGrid(dt.maxDepth, [10, 20]).build()