Python 多行在一列中共享一个值，如何将所有这些行放在一行中？

我正在处理一个文本文件，它看起来像这样：

rs001 EEE /n rs008 EEE /n rs345 EEE /n rs542 CHG /n re432 CHG /n rs001 EEE/n rs008 EEE/n rs345 EEE/n rs542 CHG/n re432 CHG/n 我希望能够将第2列中共享相同值的所有行折叠为一行（例如，

rs001 rs008 rs345 EEE

）。有没有一种简单的方法可以使用unix文本处理或python实现这一点

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谢谢

一个选项是建立一个以第2列数据为基础的字典：

#!/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))

from collections import defaultdict  #defaultdict will save a line or two of code

d = defaultdict(list)  # goal is for d to look like {'EEE':['rs001', 'rs008', ...
for line in file('data.txt', 'r'):
    v, k = line.strip().split()
    d[k].append(v)

for k, v in d.iteritems():  # print d as the strings you want
    print ' '.join(v+[k])

这种方法的优点是，它不需要将第2列的术语分组在一起（尽管问题中没有直接指定第2列是否预先分组）。

这里为您提供一个惊喜

$ awk '{a[$2]=a[$2]FS$1}END{for(i in a)print i,a[i]}' file
EEE  rs001 rs008 rs345
CHG  rs542 re432