python在hadoop上运行

1、命令样式：

        

hadoop jar $STREAM \
-files ./mapper.py,./reducer.py \
-mapper ./mapper.py \
-reducer ./reducer.py \
-input /user/$(whoami)/input/*.txt \
-output /user/$(whoami)/output

 hadoop jar share/hadoop/tools/lib/hadoop-streaming-2.7.2.jar -files source/map_temperature.py,source/reduce_temperature.py -mapper map_temperature.py -reducer reduce_temperature.py -input /input/temperature1/* -output /output/MaxTemp4

2、本地测试方法：

cat 1901.txt | python map_temperature.py | sort | python reduce_temperature.py

3、源码

mapper.py

#!/usr/bin/env python
#coding=utf-8
import re
import sys
for line in sys.stdin:
    val = line.strip()
    try:
        (year, temp, q) = (val[15:19],val[87:92],val[92:93])
    except:
        (year, temp, q) = (2014,25,1)
    # print ("{},{},{}".format(year,temp,q))
    if temp!= "+9999" and re.match("[01459]",q):
        print "%s,%s"%(year,temp)

recudce.py

#!/usr/bin/env python
#coding=utf-8
import sys
(last_key, max_val) = (None, -sys.maxint)
for line in sys.stdin:
    # print line
    # print line.strip().split(",")
    try:
        (key, val) = line.strip().split(",")
        if last_key and last_key!= key:
            print "%s,%s"%(last_key,max_val)
            (last_key, max_val) = (key, int(val))
        else:
            (last_key, max_val) = (key, max(max_val, int(val)))
    except:
        print "==================error=========================="
        continue
if last_key:
    print "%s,%s"%(last_key, max_val)