Question

I have a large tab delimited text file, for example, call it john_file:

1 john1 23 54 54
2 john2 34 45 66
3 john3 35 43 54
4 john2 34 54 78

5 john1 12 34 65
6 john3 34 55 66

What’s a quick way to parse this file into 3 lists based on name(john1, 2 or 3)?

fh=open('john_file.txt','r').readlines()
john1_list=[]
for i in fh:
 if i.split('\t')[1] == "john1":
  john1_list.append(i)

Thanks in advance

Answer 1

from collections import defaultdict

d = defaultdict(list)

with open('john_file.txt') as f:
    for line in f:
        fields = line.split('\t')
        d[fields[1]].append(line)

The individual lists are then in d['john1'], d['john2'] etc