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文章最前：我是Octopus，这个名字来源于我的中文名--章鱼；我热爱编程、热爱算法、热爱开源。所有源码在我的个人github ；这博客是记录我学习的点点滴滴，如果您对 Python、Java、AI、算法有兴趣，可以关注我的动态，一起学习，共同进步。

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PySpark 概述
Spark连接快速入门
Spark上使用pandas API快速入门

创建pyspark对象

import warnings
warnings.filterwarnings('ignore')
#import pandas as pd
#import numpy as np
from datetime import timedelta, date, datetime
import time
import gc
import os
import argparse                             
import sysfrom pyspark.sql import SparkSession, functions as fn
from pyspark.ml.feature import StringIndexer
from pyspark.ml.recommendation import ALS
from pyspark.sql.types import *
from pyspark import StorageLevel
spark = SparkSession \.builder \.appName("stockout_test") \.config("hive.exec.dynamic.partition.mode", "nonstrict") \.config("spark.sql.sources.partitionOverwriteMode", "dynamic")\.config("spark.driver.memory", '20g')\.config("spark.executor.memory", '40g')\.config("spark.yarn.executor.memoryOverhead", '1g')\.config("spark.executor.instances", 8)\.config("spark.executor.cores", 8)\.config("spark.kryoserializer.buffer.max", '128m')\.config("spark.yarn.queue", 'root.algo')\.config("spark.executorEnv.OMP_NUM_THREADS", 12)\.config("spark.executorEnv.ARROW_PRE_0_15_IPC_FORMAT", 1) \.config("spark.default.parallelism", 800)\.enableHiveSupport() \.getOrCreate()
spark.sql("set hive.exec.dynamic.partition.mode = nonstrict")
spark.sql("set hive.exec.dynamic.partition=true")
spark.sql("set spark.sql.autoBroadcastJoinThreshold=-1")

创建DataFrame

employee_salary = [("zhangsan", "IT", 8000),("lisi", "IT", 7000),("wangwu", "IT", 7500),("zhaoliu", "ALGO", 10000),("qisan", "IT", 8000),("bajiu", "ALGO", 12000),("james", "ALGO", 11000),("wangzai", "INCREASE", 7000),("carter", "INCREASE", 8000),("kobe", "IT", 9000)]columns= ["name", "department", "salary"]
df = spark.createDataFrame(data = employee_salary, schema = columns)
df.show()

+--------+----------+------+
|    name|department|salary|
+--------+----------+------+
|zhangsan|        IT|  8000|
|    lisi|        IT|  7000|
|  wangwu|        IT|  7500|
| zhaoliu|      ALGO| 10000|
|   qisan|        IT|  8000|
|   bajiu|      ALGO| 12000|
|   james|      ALGO| 11000|
| wangzai|  INCREASE|  7000|
|  carter|  INCREASE|  8000|
|    kobe|        IT|  9000|
+--------+----------+------+

row_number()

from pyspark.sql.window import Window
import pyspark.sql.functions as FwindowSpec  = Window.partitionBy("department").orderBy(F.desc("salary"))
df.withColumn("row_number", F.row_number().over(windowSpec)).show(truncate=False)

+--------+----------+------+----------+
|name    |department|salary|row_number|
+--------+----------+------+----------+
|carter  |INCREASE  |8000  |1         |
|wangzai |INCREASE  |7000  |2         |
|kobe    |IT        |9000  |1         |
|zhangsan|IT        |8000  |2         |
|qisan   |IT        |8000  |3         |
|wangwu  |IT        |7500  |4         |
|lisi    |IT        |7000  |5         |
|bajiu   |ALGO      |12000 |1         |
|james   |ALGO      |11000 |2         |
|zhaoliu |ALGO      |10000 |3         |
+--------+----------+------+----------+

Rank()

from pyspark.sql.window import Window
import pyspark.sql.functions as FwindowSpec  = Window.partitionBy("department").orderBy(F.desc("salary"))
df.withColumn("rank",F.rank().over(windowSpec)).show(truncate=False)

+--------+----------+------+----+
|name    |department|salary|rank|
+--------+----------+------+----+
|carter  |INCREASE  |8000  |1   |
|wangzai |INCREASE  |7000  |2   |
|kobe    |IT        |9000  |1   |
|qisan   |IT        |8000  |2   |
|zhangsan|IT        |8000  |2   |
|wangwu  |IT        |7500  |4   |
|lisi    |IT        |7000  |5   |
|bajiu   |ALGO      |12000 |1   |
|james   |ALGO      |11000 |2   |
|zhaoliu |ALGO      |10000 |3   |
+--------+----------+------+----+

dense_rank()

from pyspark.sql.window import Window
import pyspark.sql.functions as FwindowSpec  = Window.partitionBy("department").orderBy(F.desc("salary"))
df.withColumn("dense_rank",F.dense_rank().over(windowSpec)).show()

+--------+----------+------+----------+
|    name|department|salary|dense_rank|
+--------+----------+------+----------+
|  carter|  INCREASE|  8000|         1|
| wangzai|  INCREASE|  7000|         2|
|    kobe|        IT|  9000|         1|
|   qisan|        IT|  8000|         2|
|zhangsan|        IT|  8000|         2|
|  wangwu|        IT|  7500|         3|
|    lisi|        IT|  7000|         4|
|   bajiu|      ALGO| 12000|         1|
|   james|      ALGO| 11000|         2|
| zhaoliu|      ALGO| 10000|         3|
+--------+----------+------+----------+

lag()

from pyspark.sql.window import Window
import pyspark.sql.functions as FwindowSpec  = Window.partitionBy("department").orderBy(F.desc("salary"))
df.withColumn("lag",F.lag("salary",1).over(windowSpec)).show()

+--------+----------+------+-----+
|    name|department|salary|  lag|
+--------+----------+------+-----+
|  carter|  INCREASE|  8000| null|
| wangzai|  INCREASE|  7000| 8000|
|    kobe|        IT|  9000| null|
|zhangsan|        IT|  8000| 9000|
|   qisan|        IT|  8000| 8000|
|  wangwu|        IT|  7500| 8000|
|    lisi|        IT|  7000| 7500|
|   bajiu|      ALGO| 12000| null|
|   james|      ALGO| 11000|12000|
| zhaoliu|      ALGO| 10000|11000|
+--------+----------+------+-----+

lead()

from pyspark.sql.window import Window
import pyspark.sql.functions as FwindowSpec  = Window.partitionBy("department").orderBy(F.desc("salary"))
df.withColumn("lead",F.lead("salary", 1).over(windowSpec)).show()

+--------+----------+------+-----+
|    name|department|salary| lead|
+--------+----------+------+-----+
|  carter|  INCREASE|  8000| 7000|
| wangzai|  INCREASE|  7000| null|
|    kobe|        IT|  9000| 8000|
|zhangsan|        IT|  8000| 8000|
|   qisan|        IT|  8000| 7500|
|  wangwu|        IT|  7500| 7000|
|    lisi|        IT|  7000| null|
|   bajiu|      ALGO| 12000|11000|
|   james|      ALGO| 11000|10000|
| zhaoliu|      ALGO| 10000| null|
+--------+----------+------+-----+

Aggregate Functions

from pyspark.sql.window import Window
import pyspark.sql.functions as FwindowSpec  = Window.partitionBy("department").orderBy(F.desc("salary"))
windowSpecAgg  = Window.partitionBy("department")df.withColumn("row", F.row_number().over(windowSpec)) \.withColumn("avg", F.avg("salary").over(windowSpecAgg)) \.withColumn("sum", F.sum("salary").over(windowSpecAgg)) \.withColumn("min", F.min("salary").over(windowSpecAgg)) \.withColumn("max", F.max("salary").over(windowSpecAgg)) \.withColumn("count", F.count("salary").over(windowSpecAgg)) \.withColumn("distinct_count", F.approx_count_distinct("salary").over(windowSpecAgg)) \.show()

+--------+----------+------+---+-------+-----+-----+-----+-----+--------------+
|    name|department|salary|row|    avg|  sum|  min|  max|count|distinct_count|
+--------+----------+------+---+-------+-----+-----+-----+-----+--------------+
|  carter|  INCREASE|  8000|  1| 7500.0|15000| 7000| 8000|    2|             2|
| wangzai|  INCREASE|  7000|  2| 7500.0|15000| 7000| 8000|    2|             2|
|    kobe|        IT|  9000|  1| 7900.0|39500| 7000| 9000|    5|             4|
|zhangsan|        IT|  8000|  2| 7900.0|39500| 7000| 9000|    5|             4|
|   qisan|        IT|  8000|  3| 7900.0|39500| 7000| 9000|    5|             4|
|  wangwu|        IT|  7500|  4| 7900.0|39500| 7000| 9000|    5|             4|
|    lisi|        IT|  7000|  5| 7900.0|39500| 7000| 9000|    5|             4|
|   bajiu|      ALGO| 12000|  1|11000.0|33000|10000|12000|    3|             3|
|   james|      ALGO| 11000|  2|11000.0|33000|10000|12000|    3|             3|
| zhaoliu|      ALGO| 10000|  3|11000.0|33000|10000|12000|    3|             3|
+--------+----------+------+---+-------+-----+-----+-----+-----+--------------+

from pyspark.sql.window import Window
import pyspark.sql.functions as F
# 需要注意的是 approx_count_distinct() 函数适用于窗函数的统计，
# 而在groupby中通常用countDistinct()来代替该函数，用来求组内不重复的数值的条数。
# approx_count_distinct()取的是近似的数值，不太准确，使用需注意 windowSpec  = Window.partitionBy("department").orderBy(F.desc("salary"))
windowSpecAgg  = Window.partitionBy("department")df.withColumn("row", F.row_number().over(windowSpec)) \.withColumn("avg", F.avg("salary").over(windowSpecAgg)) \.withColumn("sum", F.sum("salary").over(windowSpecAgg)) \.withColumn("min", F.min("salary").over(windowSpecAgg)) \.withColumn("max", F.max("salary").over(windowSpecAgg)) \.withColumn("count", F.count("salary").over(windowSpecAgg)) \.withColumn("distinct_count", F.approx_count_distinct("salary").over(windowSpecAgg)) \.where(F.col("row")==1).select("department","avg","sum","min","max","count","distinct_count") \.show()

+----------+-------+-----+-----+-----+-----+--------------+ |department| avg| sum| min| max|count|distinct_count| +----------+-------+-----+-----+-----+-----+--------------+ | INCREASE| 7500.0|15000| 7000| 8000| 2| 2| | IT| 7900.0|39500| 7000| 9000| 5| 4| | ALGO|11000.0|33000|10000|12000| 3| 3| +----------+-------+-----+-----+-----+-----+--------------+

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