python脚本按行连接值并删除相同的值

Question

我使用的是 python 2.7，并且我有一个如下所示的文本文件:

id     value
---    ----
1      x
2      a
1      z
1      y
2      b

我正在尝试获得如下所示的输出:

id     value
---    ----
1      x,z,y
2      a,b

非常感谢!

Answer 1

最简单的解决方案是使用 collections.defaultdict和 collections.OrderedDict 。如果您不关心顺序，也可以使用 set 代替 OrderedDict。

from collections import defaultdict, OrderedDict

# Keeps all unique values for each id
dd = defaultdict(OrderedDict)
# Keeps the unique ids in order of appearance
ids = OrderedDict()

with open(yourfilename) as f:
    f = iter(f)
    # skip first two lines
    next(f), next(f)  
    for line in f:
        id_, value = list(filter(bool, line.split()))  # split at whitespace and remove empty ones
        dd[id_][value] = None  # dicts need a value, but here it doesn't matter which one...
        ids[id_] = None

print('id     value')
print('---    ----')
for id_ in ids:
    print('{}      {}'.format(id_, ','.join(dd[id_])))

结果:

id     value
---    ----
1      x,z,y
2      a,b

如果您想将其写入另一个文件，只需将我打印的内容与 \n 连接起来，然后将其写入到文件中。