Hello,
i'm not very experienced in python. Is there a way doing below more
memory efficient and maybe faster.
I import a 2-column file and then concat for every unique value in
the first column ( key) the value from the second
columns.
So The ouptut is something like that.
A,1,2,3
B,3,4
C,9,10,11,12,90,34,322,21
Thanks for advance & regards,
Christian
import csv
import random
import sys
from itertools import groupby
from operator import itemgetter
f=csv.reader(open(sys.argv[1]),delimiter=';')
z=[[i[0],i[1]] for i in f]
z.sort(key=itemgetter(0))
mydict = dict((k,','.join(map(itemgetter(1), it)))
for k, it in groupby(z, itemgetter(0)))
del(z)
f = open(sys.argv[2], 'w')
for k,v in mydict.iteritems():
f.write(v + "\n")
f.close()
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