根據字符長度在子列表中拆分列表

Question

我有一個字符串列表，我想根據列表中單詞的字符長度將該列表分為不同的“子列表”，例如：

List = [a, bb, aa, ccc, dddd]

Sublist1 = [a]
Sublist2= [bb, aa]
Sublist3= [ccc]
Sublist2= [dddd]

我如何在python中實現呢？

謝謝

Answer 1

通過使用itertools.groupby ：

 values = ['a', 'bb', 'aa', 'ccc', 'dddd', 'eee']
 from itertools import groupby
 output = [list(group) for key,group in groupby(sorted(values, key=len), key=len)]

結果是：

[['a'], ['bb', 'aa'], ['ccc', 'eee'], ['dddd']]

如果您的列表已經按字符串長度排序，並且只需要進行分組，那么可以將代碼簡化為：

 output = [list(group) for key,group in groupby(values, key=len)]

Answer 2

我認為您應該使用字典

>>> dict_sublist = {}
>>> for el in List:
...     dict_sublist.setdefault(len(el), []).append(el)
... 
>>> dict_sublist
{1: ['a'], 2: ['bb', 'aa'], 3: ['ccc'], 4: ['dddd']}

Answer 3

>>> from collections import defaultdict
>>> l = ["a", "bb", "aa", "ccc", "dddd"]
>>> d = defaultdict(list)
>>> for elem in l:
...     d[len(elem)].append(elem)
...
>>> sublists = list(d.values())
>>> print(sublists)
[['a'], ['bb', 'aa'], ['ccc'], ['dddd']]

Answer 4

假設您對列表列表感到滿意，該列表按長度索引，那么類似

by_length = []
for word in List:
   wl = len(word)
   while len(by_length) < wl:
      by_length.append([])
   by_length[wl].append(word)

print "The words of length 3 are %s" % by_length[3]