04 RDD编程练习

一、filter,map,flatmap练习：

1.读文本文件生成RDD lines

lines=sc.textFile("file:///usr/local/spark/mycode/rdd/word.txt")

lines.collect()

 

2.将一行一行的文本分割成单词 words

words=lines.map(lambda line:line.split())

words.collect()

 

 

3.全部转换为小写

wordsxx=lines.map(lambda word:word.lower())

wordsxx.collect()

 

 

4.去掉长度小于3的单词

word=lines.flatmap(lambda line:line.split()).filter(lambda words:len(words)>2)

word.collect()

 

 

5.去掉停用词

lines=textFile("file///usr/local/spark/mycode/rdd/word.txt")

with open("/usr/lcaol/spark/mycode/rdd/stopwords.txt") as f:

      stops=f.read().split()

lines.flatMap(lambda line:line.split()).filter(lambda word:word not in stops).collect()

 

 

二、groupByKey练习

6.练习一的生成单词键值对

words=lines.flatMap(lambda line:line.split()).map(lambda word:(word,1))

words.collect()

 

 

7.对单词进行分组

words1=words.groupByKey()

8.查看分组结果

words1.collect()

 

 

学生科目成绩文件练习：

0.数据文件上传

1.读大学计算机系的成绩数据集生成RDD

lines=textFile("file///usr/local/spark/mycode/rdd/xs.txt")

lines.take(3)

 

 

2.按学生汇总全部科目的成绩

groupName=lines.flatMap(lambda line:line.split(',')).map(lambda line:(line[0],(line[1],line[2]))).groupByKey()

groupName.take(3)

for i in groupName.first()[1]:

    print(i)

 

 

3.按科目汇总学生的成绩

 groupKm=lines.flatMap(lambda line:line.split(',')).Map(word:(word[1],(word[0],word[2]))).groupByKey()

groupKm.take(3)

for j in groupKm.first()[1]

    print(j)