擅长:python、mysql、java
<pre><code>#!/usr/bin/env python
from __future__ import with_statement
from itertools import groupby
with open('file','r') as f:
# We define "it" to be an iterator, for each line
# it yields pairs like ('rs001','EEE')
it=(line.strip().split() for line in f)
# groupby does the heave work.
# lambda p: p[1] is the keyfunction. It groups pairs according to the
# second element, e.g. 'EEE'
for key,group in groupby(it,lambda p: p[1]):
# group might be something like [('rs001','EEE'),('rs008','EEE'),...]
# key would be something like 'EEE', the value that we're grouping by.
print('%s %s'%(' '.join([p[0] for p in group]),key))
</code></pre>