Python:基于单词的第一个字符拆分列表

Question

我有点卡在一个问题上,我已经四处走动,直到我迷惑自己.

我要做的是拿一个单词列表:

['About', 'Absolutely', 'After', 'Aint', 'Alabama', 'AlabamaBill', 'All', 'Also', 'Amos', 'And', 'Anyhow', 'Are', 'As', 'At', 'Aunt', 'Aw', 'Bedlam', 'Behind', 'Besides', 'Biblical', 'Bill', 'Billgone']

然后按照字母顺序对它们进行排序:

A
About
Absolutely
After

B
Bedlam
Behind

等等...

有没有简单的方法来做到这一点？

Answer 1

用于itertools.groupby()按特定键对输入进行分组,例如第一个字母:

from itertools import groupby
from operator import itemgetter

for letter, words in groupby(sorted(somelist), key=itemgetter(0)):
    print letter
    for word in words:
        print word
    print

如果您的列表已经排序,则可以省略该sorted()呼叫.该itemgetter(0)调用将返回每个单词(索引0处的字符)的第一个字母,并且groupby()然后将产生键加上只包含的量,键保持相同的那些项目可迭代.在这种情况下,这意味着循环words将为您提供以相同字符开头的所有项目.

演示:

>>> somelist = ['About', 'Absolutely', 'After', 'Aint', 'Alabama', 'AlabamaBill', 'All', 'Also', 'Amos', 'And', 'Anyhow', 'Are', 'As', 'At', 'Aunt', 'Aw', 'Bedlam', 'Behind', 'Besides', 'Biblical', 'Bill', 'Billgone']
>>> from itertools import groupby
>>> from operator import itemgetter
>>> 
>>> for letter, words in groupby(sorted(somelist), key=itemgetter(0)):
...     print letter
...     for word in words:
...         print word
...     print
... 
A
About
Absolutely
After
Aint
Alabama
AlabamaBill
All
Also
Amos
And
Anyhow
Are
As
At
Aunt
Aw

B
Bedlam
Behind
Besides
Biblical
Bill
Billgone