安装Python并不是安装Spark的必需步骤,因为Python和Spark是两个独立的组件。但是,安装Python是进行数据分析、数据处理和机器学习时常用的一个语言。因此,我们在这里提供一个Python安装Spark的详细过程攻略。
首先,我们需要在计算机上安装Python。Python有两个主要版本:Python 2和Python 3。推荐选择安装Python 3,因为Python 2已经不再被维护。
我们可以通过以下步骤来安装Python:
接下来,我们需要安装Spark。Spark有多种安装方式,这里只介绍最常见的两种方式:使用二进制文件安装和使用源代码安装。
二进制文件是Spark已经编译好的二进制文件。你只需要下载Spark的二进制文件并解压缩即可使用。
你可以按照以下步骤来安装Spark:
$SPARK_HOME/bin/run-example SparkPi 10
使用源代码安装Spark需要先安装Java和Scala的运行环境,然后下载Spark的源代码并手动编译和构建。
你可以按照以下步骤来安装Spark:
$SPARK_HOME/sbin/start-all.sh
来启动Spark。运行Spark SQL程序需要使用Python。我们假设你已经正确安装了Python和Spark。
运行以下的Python程序,可以连接到Spark中的数据库,并执行查询:
from pyspark.sql import SparkSession
spark = SparkSession.builder \
.appName("Python Spark SQL basic example") \
.config("spark.some.config.option", "some-value") \
.getOrCreate()
df = spark.read \
.format("jdbc") \
.option("url", "jdbc:mysql://localhost:3306/mydatabase") \
.option("dbtable", "customers") \
.option("user", "root") \
.option("password", "root") \
.load()
df.show()
spark.stop()
假设你已经正确安装了Python和Spark,以及下载并解压Titanic数据集。
你可以按照以下步骤来训练一个简单的Spark MLlib分类器:
from pyspark.ml.feature import StringIndexer
from pyspark.ml.tuning import CrossValidator, ParamGridBuilder
from pyspark.ml.classification import RandomForestClassifier, LogisticRegression, NaiveBayes
from pyspark.ml.evaluation import BinaryClassificationEvaluator
from pyspark.ml import Pipeline
from pyspark.sql import SparkSession
from pyspark.sql.types import StructType, StructField, StringType, DoubleType
import os
spark = SparkSession.builder \
.appName("Titanic Classification") \
.getOrCreate()
categoryIndexer1 = StringIndexer(inputCol="_c1", outputCol="sex")
categoryIndexer2 = StringIndexer(inputCol="_c4", outputCol="embarked")
categoryIndexer3 = StringIndexer(inputCol="_c11", outputCol="survived")
schema = StructType([
StructField("_c0", DoubleType(), True),
StructField("_c1", StringType(), True),
StructField("_c2", DoubleType(), True),
StructField("_c3", DoubleType(), True),
StructField("_c4", StringType(), True),
StructField("_c5", DoubleType(), True),
StructField("_c6", DoubleType(), True),
StructField("_c7", StringType(), True),
StructField("_c8", DoubleType(), True),
StructField("_c9", StringType(), True),
StructField("_c10", DoubleType(), True),
StructField("_c11", StringType(), True)
])
df = spark.read.csv("train.csv",header=False,schema=schema)
df = df.fillna(0)
features = ["sex", "age", "embarked", "pclass"]
stages = [categoryIndexer1, categoryIndexer2, categoryIndexer3]
pipe = Pipeline(stages=stages)
model = pipe.fit(df)
df = model.transform(df)
(training, test) = df.randomSplit([0.8, 0.2], seed=42)
classifier1 = RandomForestClassifier(labelCol="survived", featuresCol="features", numTrees=10, maxDepth=5)
classifier2 = LogisticRegression(maxIter=100, featuresCol="features", labelCol="survived")
classifier3 = NaiveBayes(smoothing=1.0, modelType="multinomial", featuresCol="features", labelCol="survived")
pipeline1 = Pipeline(stages=stages+[classifier1])
pipeline2 = Pipeline(stages=stages+[classifier2])
pipeline3 = Pipeline(stages=stages+[classifier3])
evaluator=BinaryClassificationEvaluator(labelCol="survived")
paramGrid1 = ParamGridBuilder() \
.addGrid(classifier1.numTrees, [5, 10]) \
.addGrid(classifier1.maxDepth, [2, 5]) \
.build()
paramGrid2 = ParamGridBuilder() \
.addGrid(classifier2.regParam, [0.01, 0.1, 0.5]) \
.build()
paramGrid3 = ParamGridBuilder() \
.build()
cv1 = CrossValidator(estimator=pipeline1, evaluator=evaluator, estimatorParamMaps=paramGrid1, numFolds=5)
cv2 = CrossValidator(estimator=pipeline2, evaluator=evaluator, estimatorParamMaps=paramGrid2, numFolds=5)
cv3 = CrossValidator(estimator=pipeline3, evaluator=evaluator, estimatorParamMaps=paramGrid3, numFolds=5)
cvModel1 = cv1.fit(training)
cvModel2 = cv2.fit(training)
cvModel3 = cv3.fit(training)
bestModel1 = cvModel1.bestModel
bestModel2 = cvModel2.bestModel
bestModel3 = cvModel3.bestModel
predictions1 = bestModel1.transform(test)
predictions2 = bestModel2.transform(test)
predictions3 = bestModel3.transform(test)
auc1 = evaluator.evaluate(predictions1)
auc2 = evaluator.evaluate(predictions2)
auc3 = evaluator.evaluate(predictions3)
print("RandomForest AUC: ",auc1)
print("LogisticRegression AUC: ",auc2)
print("NaiveBayes AUC: ",auc3)
spark.stop()
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