多行在一個列中共享一個值，如何將所有這些行放到一個行中？

Question

我正在使用一個看起來像這樣的文本文件：

rs001  EEE /n
rs008  EEE /n
rs345  EEE /n
rs542  CHG /n
re432  CHG /n

我希望能夠將第2列中共享相同值的所有行折疊到單個行中（例如rs001 rs008 rs345 EEE ）。 是否有使用Unix文本處理或python的簡單方法？

謝謝

Answer 1

#!/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))

Answer 2

一種選擇是建立以第2列數據為鍵的字典：

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])

這種方法的優點是不需要將第2列的術語歸為一組（盡管在問題中未直接指定第2列是否為預先分組的）。

Answer 3

這是給你的傻瓜

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