Mapping Single Rows to Multiple Pairs
目的：

把如下的这种数据，

Input Data

00001 sku010:sku933:sku022
00002 sku912:sku331
00003 sku888:sku022:sku010:sku594
00004 sku411

转换为这样：
一个Key值，带的这几个键值，分别罗列：

(00001,sk010)
(00001,sku933)
(00001,sku022)

...
(00002,sku912)
(00002,sku331)
(00003,sku888)

这就是所谓的 Mapping Single Rows to Multiple Pairs

步骤如下：

[training@localhost ~]$ vim act001.txt
[training@localhost ~]$ 
[training@localhost ~]$ cat act001.txt
00001 ku010:sku933:sku022
00002 sku912:sku331
00003 sku888:sku022:sku010:sku594
00004 sku411
[training@localhost ~]$ hdfs dfs -put act001.txt
[training@localhost ~]$ 
[training@localhost ~]$ hdfs dfs -cat act001.txt
00001 ku010:sku933:sku022
00002 sku912:sku331
00003 sku888:sku022:sku010:sku594
00004 sku411
[training@localhost ~]$

In [6]: mydata01=mydata.map(lambda line: line.split("\t"))

In [7]: type(mydata01)
Out[7]: pyspark.rdd.PipelinedRDD

In [8]: mydata02=mydata01.map(lambda fields: (fields[0],fields[1]))

In [9]: type(mydata02)
Out[9]: pyspark.rdd.PipelinedRDD

In [10]:

In [11]: mydata03 = mydata02.flatMapValues(lambda skus: skus.split(":"))

In [12]: type(mydata03)
Out[12]: pyspark.rdd.PipelinedRDD

In [13]: mydata03.take(1)
Out[13]: [(u'00001', u'ku010')]

本文转自健哥的数据花园博客园博客，原文链接：http://www.cnblogs.com/gaojian/p/7603900.html，如需转载请自行联系原作者