python - 在某些条件下组合列表元素

Question

如果满足某些条件，我如何组合列表的元素。

我看到过关于组合列表元素的帖子，但不是在某些条件下。

假设我有一个包含单词列表的列表:

words = [
    ['this','that!','riff','raff'],
    ['hip','hop!','flip!','flop'],
    ['humpty','dumpty!','professor!','grumpy!']
]

如何只组合那些包含 ! 的元素？

例如，输出如下所示:

[['this', 'that!', 'riff', 'raff'],
 ['hip', 'hop!, flip!', 'flop'],  # 1,2 are now combined
 ['humpty', 'dumpty!, professor!, grumpy!']]   # 1,2,3 are now combined

我试过这个:

for word in words:
    word = ', '.join(i for i in word if re.search('!',str(i)))
    print word

但是得到了:

that!
hop!, flip!
dumpty!, professor!, grumpy!

谢谢。

Answer 1

使用itertools.groupby :

>>> from itertools import groupby
>>> out = []
>>> for lst in words:
    d = []
    for k, g in groupby(lst, lambda x: '!' in x):
        if k:
            d.append(', '.join(g))
        else:
            d.extend(g)
    out.append(d)
...     
>>> out
[['this', 'that!', 'riff', 'raff'],
 ['hip', 'hop!, flip!', 'flop'],
 ['humpty', 'dumpty!, professor!, grumpy!']]