human
!python MRJob_PreprocessGraph_topic.py randNet.txt --file 'randNet_topics.txt' --jobconf 'G=100' --jobconf 'topicIdxFilename=randNet_topics.txt' -r emr --num-ec2-instances 2 --ec2-task-instance-type m1.medium --output-dir s3://ucb-mids-mls-katieadams/output-wiki-preprocess-topics --no-output

!head -1 randNet_input.txt

from collections import defaultdict
def numNodesByTopic(topicsIdxFile, topicsCountFile):
    numNodesTopic = defaultdict(int)
    with open('randNet_topics.txt', 'r') as f:
        for line in f.readlines():
            line = line.strip()
            p,t = line.split('\t')
            numNodesTopic[int(t)]+=1
            numNodesTopic['*']+=1
    with open('randNet_topicCount.txt','w') as f:
        for k,v in numNodesTopic.iteritems():
            line = str(k)+'\t'+str(v)+'\n'
            f.write(line)

            
topicsIdxFile, topicsCountFile
numNodesByTopic(topicsIdxFile, topicsCountFile)

!cat randNet_topicCount.txt

%%writefile MRJob_PageRank_Topic.py
#!/usr/bin/env python
from mrjob.job import MRJob
from mrjob.step import MRStep   
from ast import literal_eval
from mrjob.compat import jobconf_from_env
import sys

class MRJobPageRankTopic(MRJob):
    
    
    def configure_options(self):
        super(MRJobPageRankTopic, self).configure_options()
        
        self.add_passthrough_option(
                '--iterations',
                dest = 'iterations',
                default = 10,
                type='int',
                help='number of iterations to run')
    

    def steps(self):        
        
        mapper_only = 0
        if mapper_only:
            return [MRStep(mapper = self.mapper_firstiter)]
        
        return [MRStep(
                mapper = self.mapper_firstiter,
                reducer_init = self.reducer_init,
                reducer = self.reducer
                ),
               MRStep(
                reducer = self.reducer_redistr)]+\
                [MRStep(
                mapper = self.mapper,
                reducer_init =...
Given the above code, generate some markdown instructions for it.

What is a the Python code you requested?
assistant
#Here is the Python code you requested.

Test preprocessing on emr