pyspark 记录
import os
import sys
spark_name = os.environ.get('SPARK_HOME',None)
if not spark_name:
raise ValueErrorError('spark环境没有配置好')
sys.path.insert(0,os.path.join(spark_name,'python'))
sys.path.insert(0,os.path.join(spark_name,'python/lib/py4j-0.10.4-src.zip'))
import pyspark
from pyspark import SparkConf
from pyspark.context import SparkContext
from pyspark.sql import SparkSession, SQLContext
sc = SparkContext(appName="MyProject")
yarn 模式报No module named pyspark
## 初始化 SparkContext
from pyspark import SparkConf,SparkContext
conf = (SparkConf()
.setMaster('local[20]')
.setAppName('my spark app')
.set("spark.executor.memory",'10g'))
sc = SparkContext(conf=conf)
# 或者
sc = SparkContext(appName="my spark app",master='local')
## 打印 SparkContext 相关信息
print(sc.version)
print(sc.pythonVer)
print(sc.master)
print(sc.sparkHome)
print(sc.sparkUser())
print(sc.appName)
print(sc.applicationId)
print(sc.defaultParallelism)
print(sc.defaultMinPartitions)
RDD 操作
查看基础统计信息
rdd = sc.parallelize([('a',1),('b',4),('a',5)])
print(rdd.getNumPartitions())
print(rdd.count())
print(rdd.countByKey())
print(rdd.countByValue())
print(rdd.collectAsMap())
1
3
defaultdict(<class 'int'>, {'a': 2, 'b': 1})
defaultdict(<class 'int'>, {('a', 1): 1, ('b', 4): 1, ('a', 5): 1})
{'a': 5, 'b': 4}
## 对一维RDD
rdd = sc.parallelize([random.randint(0,20) for i in range(10)])
print(rdd.collect())
print(sorted(rdd.collect()))
print(rdd.max())
print(rdd.min())
print(rdd.mean())
print(rdd.stdev())
print(rdd.stats())
print(rdd.histogram(3))
[20, 3, 7, 19, 7, 20, 20, 5, 16, 2]
[2, 3, 5, 7, 7, 16, 19, 20, 20, 20]
20
2
11.9
7.327346040688948
(count: 10, mean: 11.9, stdev: 7.327346040688948, max: 20.0, min: 2.0)
([2, 8, 14, 20], [5, 0, 5])
应用函数
import random
file_name = path + 'data_random'
data_random = [[random.randint(0,20) for j in range(5)] for i in range(3)]
rdd = sc.parallelize(data_random)
rdd1 = rdd.map(lambda x:sorted(x))
print(rdd1.collect())
rdd2 = rdd.flatMap(lambda x:sorted(x))
print(rdd2.collect())
[[0, 5, 8, 13, 20], [0, 3, 3, 9, 11], [3, 4, 7, 11, 17]]
[0, 5, 8, 13, 20, 0, 3, 3, 9, 11, 3, 4, 7, 11, 17]
rdd = sc.parallelize([('a',[3,4,5,6]),('b',[11,22,33,44]),('a',[1111,2222])]) ## 注意这里是tuple（）
rdd1 = rdd.mapValues(lambda x:len(x))
print(rdd1.collect())
print(rdd.reduceByKey(lambda x,y:x+y).collect())
# groupByKey()：应用于(K,V)键值对的数据集时，返回一个新的(K, Iterable)形式的数据集
print(rdd.reduce(lambda x,y:x+y)) ## tuple的加法
[('a', 4), ('b', 4), ('a', 2)]
[('a', [3, 4, 5, 6, 1111, 2222]), ('b', [11, 22, 33, 44])]
('a', [3, 4, 5, 6], 'b', [11, 22, 33, 44], 'a', [1111, 2222])
rdd = sc.parallelize([i for i in range(10)])
print(rdd.collect())
print(rdd.reduce(lambda x,y:x+y))
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
45
rdd = sc.parallelize([i for i in range(5)])
print(rdd.collect())
print(rdd.keyBy(lambda x:chr(ord('a')+x)).collect()) ##给每个元素添加key
[0, 1, 2, 3, 4]
[('a', 0), ('b', 1), ('c', 2), ('d', 3), ('e', 4)]
选择数据
data_random = [[random.randint(0,20) for j in range(5)] for i in range(3)]
rdd = sc.parallelize(data_random)
print(rdd.collect())
print(rdd.first()) ## 返回第一个元素
print(rdd.take(2)) ## 以list形式返回前俩个元素
print(rdd.top(2))
[[2, 10, 8, 15, 8], [7, 5, 6, 17, 0], [18, 17, 7, 9, 13]]
[2, 10, 8, 15, 8]
[[2, 10, 8, 15, 8], [7, 5, 6, 17, 0]]
[[18, 17, 7, 9, 13], [7, 5, 6, 17, 0]]
## 抽样
data_random = [[random.randint(0,20) for j in range(5)] for i in range(100)]
rdd = sc.parallelize(data_random)
print(rdd.count())
rdd_sample = rdd.sample(withReplacement=False,fraction=0.3,seed=123)
print(rdd_sample.count())
100
31
## 过滤(返回满足条件的元素)
rdd = sc.parallelize([random.randint(0,10) for i in range(20)])
print(rdd.collect())
rdd_filtered = rdd.filter(lambda x:ｘ>5)
print(rdd_filtered.collect())
[7, 10, 0, 4, 1, 5, 7, 2, 4, 2, 10, 2, 9, 10, 6, 5, 8, 0, 5, 2]
[7, 10, 7, 10, 9, 10, 6, 8]
## 得到不同元素
rdd = sc.parallelize([1,2,3,4,5,6,1,2,3,4,5])
print(rdd.collect())
print(rdd.distinct().collect())
[1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5]
[1, 2, 3, 4, 5, 6]
rdd = sc.parallelize([('a',[3,4,5,6]),('b',[11,22,33,44]),('a',[1111,2222])])
print(rdd.keys().collect())
print(rdd.values().collect())
['a', 'b', 'a']
[[3, 4, 5, 6], [11, 22, 33, 44], [1111, 2222]]
聚合
rdd = sc.parallelize([i for i in range(50)])
rdd_groupby = rdd.groupBy(lambda x: x % 3)
print(rdd_groupby.collect())
print(rdd_groupby.mapValues(list).collect())
print(rdd_groupby.map(lambda x:(x[0],list(x[1]))).collect())
[(0, <pyspark.resultiterable.ResultIterable object at 0x7f2359670be0>), (1, <pyspark.resultiterable.ResultIterable object at 0x7f2359670a58>), (2, <pyspark.resultiterable.ResultIterable object at 0x7f2359717be0>)]
[(0, [0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48]), (1, [1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46, 49]), (2, [2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, 35, 38, 41, 44, 47])]
[(0, [0, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48]), (1, [1, 4, 7, 10, 13, 16, 19, 22, 25, 28, 31, 34, 37, 40, 43, 46, 49]), (2, [2, 5, 8, 11, 14, 17, 20, 23, 26, 29, 32, 35, 38, 41, 44, 47])]
from operator import add
sc.parallelize([1, 2, 3, 4, 5]).fold(0, add)
15
## 对分区分别处理
sc.parallelize([1,2,3,4]).aggregate(
(0, 0),
(lambda acc, value: (acc[0] + value, acc[1] + 1)),
(lambda acc1, acc2: (acc1[0] + acc2[0], acc1[1] + acc2[1])))
(10, 4)
list(range(10))
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
## 集合运算
rdd1 = sc.parallelize(list(range(10)))
rdd2 = sc.parallelize(list(range(5,15)))
rdd3 = rdd2.subtract(rdd1) ## 返回rdd2和rdd1的差集
print(rdd3.collect())
[10, 12, 14, 11, 13]
rdd1 = sc.parallelize([('a',1),('b',2),('c',3)])
rdd2 = sc.parallelize([('a',1),('b',2),('d',4)])
rdd3 = rdd2.subtractByKey(rdd1) ## 根据key计算差集
print(rdd3.collect())
[('d', 4)]
rdd1 = sc.parallelize(list(range(3)))
rdd2 = sc.parallelize(list(range(5,8)))
rdd3 = rdd1.cartesian(rdd2) ## 笛卡尔积
print(rdd3.collect())
[(0, 5), (0, 6), (0, 7), (1, 5), (1, 6), (1, 7), (2, 5), (2, 6), (2, 7)]
##将rdd重新分区
rdd = rdd.repartition(4) # 需要重新赋值
rdd = rdd.coalesce(2) ## # 需要重新赋值
print(rdd.getNumPartitions())
2
## 保存
rdd.saveAsTextFile(path)
rdd.saveAsHadoopFile(path)
...
DataFrame
from pyspark.sql import SparkSession
spark = SparkSession(sc)
## 从rdd创建df
from pyspark.sql.types import *
from pyspark.sql import Row
##从rdd推断schema
rdd = sc.parallelize([[i,chr(i+97)] for i in range(5)])
print(rdd.collect())
rdd = rdd.map(lambda x:Row(No=x[0],char=x[1]))
print(rdd.collect())
df = spark.createDataFrame(rdd)
df.show()
[[0, 'a'], [1, 'b'], [2, 'c'], [3, 'd'], [4, 'e']]
[Row(No=0, char='a'), Row(No=1, char='b'), Row(No=2, char='c'), Row(No=3, char='d'), Row(No=4, char='e')]
+---+----+
| No|char|
+---+----+
| 0| a|
| 1| b|
| 2| c|
| 3| d|
| 4| e|
+---+----+
## 指定schema
rdd = sc.parallelize([Row(No=i,char=chr(i+97)) for i in range(5)])
print(rdd.collect())
schema_list = ['No','char']
fields = [StructField(name='No',dataType=IntegerType(),nullable=True),
StructField(name='char',dataType=StringType(),nullable =True)]
schema = StructType(fields)
df = spark.createDataFrame(rdd)
df.show()
[Row(No=0, char='a'), Row(No=1, char='b'), Row(No=2, char='c'), Row(No=3, char='d'), Row(No=4, char='e')]
+---+----+
| No|char|
+---+----+
| 0| a|
| 1| b|
| 2| c|
| 3| d|
| 4| e|
+---+----+
##保存dataframe到文件
df.select('*').write.save(path+'df.parquet')
df.select('*').write.save(path+'df.json',format='json')
##从spark文件读入
df=spark.read.load(path+"df.parquet")
print(df.show())
df=spark.read.load(path+"df.json",format='json')
print(df.show())
df=spark.read.json(path+'df.json')
print(df.show())
+---+----+
| No|char|
+---+----+
| 0| a|
| 1| b|
| 2| c|
| 3| d|
| 4| e|
+---+----+
None
+---+----+
| No|char|
+---+----+
| 0| a|
| 1| b|
| 2| c|
| 3| d|
| 4| e|
+---+----+
None
+---+----+
| No|char|
+---+----+
| 0| a|
| 1| b|
| 2| c|
| 3| d|
| 4| e|
+---+----+
None
## 检查dataframe数据
print(df.dtypes)
print(df.schema)
print(df.show())
print(df.first())
print(df.take(1))
print(df.describe().show())
[('No', 'bigint'), ('char', 'string')]
StructType(List(StructField(No,LongType,true),StructField(char,StringType,true)))
+---+----+
| No|char|
+---+----+
| 0| a|
| 1| b|
| 2| c|
| 3| d|
| 4| e|
+---+----+
None
Row(No=0, char='a')
[Row(No=0, char='a')]
+-------+------------------+----+
|summary| No|char|
+-------+------------------+----+
| count| 5| 5|
| mean| 2.0|null|
| stddev|1.5811388300841898|null|
| min| 0| a|
| max| 4| e|
+-------+------------------+----+
None
print(df.columns)
print(df.count())
print(df.distinct().count())
print(df.printSchema())
print(df.explain()) ##
['No', 'char']
5
5
root
|-- No: long (nullable = true)
|-- char: string (nullable = true)
None
== Physical Plan ==
*FileScan json [No#1051L,char#1052] Batched: false, Format: JSON, Location: InMemoryFileIndex[afs://baihua.afs.baidu.com:9902/user/fpd_dm/tangshengyu/spark/df.json], PartitionFilters: [], PushedFilters: [], ReadSchema: struct<No:bigint,char:string>
None
dataframe查询
## select
from pyspark.sql import functions as F
rdd = sc.parallelize([Row(No=1,char='a',values=[1,2]),Row(No=2,char='b',values=[1,4])])
df = spark.createDataFrame(rdd)
print(df.select('No').show())
print(df.select('No','char',F.explode('values').alias('value')).show()) ## 将聚合的列展开
print(df.select(df['No']+1,df['char']).show()) ## 对整列进行运算
+---+
| No|
+---+
| 1|
| 2|
+---+
None
+---+----+-----+
| No|char|value|
+---+----+-----+
| 1| a| 1|
| 1| a| 2|
| 2| b| 1|
| 2| b| 4|
+---+----+-----+
None
+--------+----+
|(No + 1)|char|
+--------+----+
| 2| a|
| 3| b|
+--------+----+
None
print(df.select(df['No']>1).show()) ## 条件查询
print(df.select('No','char',F.when(df.char=='a',1).otherwise(0).alias('is a')).show()) ## 根据已有列产生新列
print(df[df.char.isin('a')].show()) ##条件查询
print(df.select('No',df.char.like('a')).show()) ## 根据已有列产生新列
+--------+
|(No > 1)|
+--------+
| false|
| true|
+--------+
None
+---+----+----+
| No|char|is a|
+---+----+----+
| 1| a| 1|
| 2| b| 0|
+---+----+----+
None
+---+----+------+
| No|char|values|
+---+----+------+
| 1| a|[1, 2]|
+---+----+------+
None
+---+-----------+
| No|char LIKE a|
+---+-----------+
| 1| true|
| 2| false|
+---+-----------+
None
print(df.select('No',df.char.startswith('a')).show()) ## 以指定字符开始
print(df.select('No',df.char.endswith('b')).show())
+---+-------------------+
| No|startswith(char, a)|
+---+-------------------+
| 1| true|
| 2| false|
+---+-------------------+
None
+---+-----------------+
| No|endswith(char, b)|
+---+-----------------+
| 1| false|
| 2| true|
+---+-----------------+
None
rdd = sc.parallelize([Row(No=1,char='aaaaa',values=[1,2]),Row(No=2,char='bbbbb',values=[1,4])])
df = spark.createDataFrame(rdd)
print(df.select('No',df.char.substr(1,3)).show())
print(df.select(df.No.between(0,1)).show())
+---+---------------------+
| No|substring(char, 1, 3)|
+---+---------------------+
| 1| aaa|
| 2| bbb|
+---+---------------------+
None
+-------------------------+
|((No >= 0) AND (No <= 1))|
+-------------------------+
| true|
| false|
+-------------------------+
None
## 增加列
df = df.withColumn('new_col',df.char)
print(df.show())
df = df.withColumnRenamed('new_col','renamed_col')
print(df.show())
+---+-----+------+-------+
| No| char|values|new_col|
+---+-----+------+-------+
| 1|aaaaa|[1, 2]| aaaaa|
| 2|bbbbb|[1, 4]| bbbbb|
+---+-----+------+-------+
None
+---+-----+------+-----------+
| No| char|values|renamed_col|
+---+-----+------+-----------+
| 1|aaaaa|[1, 2]| aaaaa|
| 2|bbbbb|[1, 4]| bbbbb|
+---+-----+------+-----------+
None
## 删除列
df = df.drop("renamed_col")
print(df.show())
df = df.drop(df.values)
print(df.show())
+---+-----+------+
| No| char|values|
+---+-----+------+
| 1|aaaaa|[1, 2]|
| 2|bbbbb|[1, 4]|
+---+-----+------+
None
+---+-----+
| No| char|
+---+-----+
| 1|aaaaa|
| 2|bbbbb|
+---+-----+
None
## groupby
rdd = sc.parallelize([Row(No=1,char='aaaaa',values=[1,2]),
Row(No=2,char='bbbbb',values=[1,4]),
Row(No=1,char='ccccc',values=[3,5])])
df = spark.createDataFrame(rdd)
print(df.groupBy('No').count().show()) # 区别？
print(df.groupby('No').count().show()) # 区别？
+---+-----+
| No|count|
+---+-----+
| 1| 2|
| 2| 1|
+---+-----+
None
+---+-----+
| No|count|
+---+-----+
| 1| 2|
| 2| 1|
+---+-----+
None
print(df.filter(df.No>1).show())
+---+-----+------+
| No| char|values|
+---+-----+------+
| 2|bbbbb|[1, 4]|
+---+-----+------+
None
## sort
print(df.sort(df.No.desc()).show()) ## 降序， 升序是asc
print(df.orderBy(['No','char'],asciiending=[1,1]).show()) ##
+---+-----+------+
| No| char|values|
+---+-----+------+
| 2|bbbbb|[1, 4]|
| 1|aaaaa|[1, 2]|
| 1|ccccc|[3, 5]|
+---+-----+------+
None
+---+-----+------+
| No| char|values|
+---+-----+------+
| 1|aaaaa|[1, 2]|
| 1|ccccc|[3, 5]|
| 2|bbbbb|[1, 4]|
+---+-----+------+
None
## 值替换和缺失值填充
rdd = sc.parallelize([Row(No=1,char='aaaaa',values=[1,2]),
Row(No=2,char='bbbbb',values=[1,4]),
Row(No=1,char='ccccc',values=[3,5])])
df = spark.createDataFrame(rdd)
print(df.show())
print(df.na.fill('eeee').show())
print(df.na.drop().show()) ## 删除有空值的行
print(df.na.replace(1,10).show()) ## 对指定值进行替换
+---+-----+------+
| No| char|values|
+---+-----+------+
| 1|aaaaa|[1, 2]|
| 2|bbbbb|[1, 4]|
| 1|ccccc|[3, 5]|
+---+-----+------+
None
+---+-----+------+
| No| char|values|
+---+-----+------+
| 1|aaaaa|[1, 2]|
| 2|bbbbb|[1, 4]|
| 1|ccccc|[3, 5]|
+---+-----+------+
None
+---+-----+------+
| No| char|values|
+---+-----+------+
| 1|aaaaa|[1, 2]|
| 2|bbbbb|[1, 4]|
| 1|ccccc|[3, 5]|
+---+-----+------+
None
+---+-----+------+
| No| char|values|
+---+-----+------+
| 10|aaaaa|[1, 2]|
| 2|bbbbb|[1, 4]|
| 10|ccccc|[3, 5]|
+---+-----+------+
None
## 分区相关
print(df.repartition(3).rdd.getNumPartitions())
print(df.coalesce(1).rdd.getNumPartitions())
3
1
## 用SQL进行操作
## 建立视图
#df.createGlobalTempView('demo') #across spark sessions
df.createOrReplaceTempView('demo') # spark session lifetime
#df.createTempView('demo')
spark.sql("select * from demo").show()
+---+-----+------+
| No| char|values|
+---+-----+------+
| 1|aaaaa|[1, 2]|
| 2|bbbbb|[1, 4]|
| 1|ccccc|[3, 5]|
+---+-----+------+
## 转其它数据
df.toJSON()
df.toPandas()
df.rdd.take(1)
# 终止会话
spark.stop()
pipline for model
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