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+--- Thread: understand function (/thread-4656.html)
understand function - hermann - Sep-01-2017
I did not understand how this function works properly? can anyone help me to understand it and to test it?. i work with csv file
# Convert each line into a dictionary dict(zip(cols, [ a.strip() for a in csv.reader([line]).next()]))
RE: understand function - buran - Sep-01-2017
[a.strip()for a in csv.reader([line]).next()]this will create a list.
zip(cols, [ a.strip() for a in csv.reader([line]).next()])this will create list of 2-element tuples, assuming cols is also iterable
dict(zip(cols, [ a.strip() for a in csv.reader([line]).next()]))this will create dict out of the tuples - first element in the tuple used as a key, second element - as item.
All that said it could be written way better. Could you post your entire code - i.e. where cols and line comes from
RE: understand function - hermann - Sep-01-2017
I have two files, from which I need to get ip and port information or more generally find what is equal or what is different using mrjob. The following code is a draft of what I'm trying to do.
from mrjob.job import MRJob
import csv
cols='ipv,vvv.vvv.vvv'.split(',')
def parse_line(line_str):
return dict(zip(cols,[a.strip() for a in csv.reader([line_str]).next()]))
def parse_ip_address(ip_str):
ip=ip_str;
return ip
def parse_port(p_str):
port=p_str;
return (port)
class Myclass(MRJob):
def mapper(self, _, line):
#parse the line from current CVS form
p1=parse_line(line)
#get ip
ip_address=parse_ip_address(p1['vvv.vvv.vvv'])
#get port
port=parse_port(p1['ipv'])
#yield a key and a value
yield port,ip_address
#reducer function
def reducer(self, key, values):
yield key
if __name__ == '__main__':
Myclass.run()
RE: understand function - hermann - Sep-06-2017
I have the python code for comparing the two files, but I did not understand how to use it on mrjob.