[英]Split list into lists by particular value
我有一个清单:
['S1', 'S2', 'S6', 'S1', 'S2', 'S3', 'S4', 'S5', 'S1', 'S2', 'S5', 'S1',
'S2', 'S4', 'S5', 'S1', 'S2', 'S4', 'S5', 'S1', 'S2', 'S3', 'S6']
我想在下一个 S1 之前拆分:
[['S1', 'S2', 'S6']['S1', 'S2', 'S3', 'S4', 'S5'],['S1', 'S2', 'S4', 'S5]...]
我的代码是:
size = len(steps)
idx_list = [idx + 1 for idx, val in
enumerate(steps) if val == 'S1']
res = [steps[i: j] for i, j in
zip([0] + idx_list, idx_list +
([size] if idx_list[-1] != size else []))]
print("The list after splitting by a value : " + str(res))
它将列表拆分为:
[['S1'], ['S2', 'S6', 'S1'], ['S2', 'S3', 'S4', 'S5', 'S1'],
['S2', 'S5', 'S1'], ['S2', 'S4', 'S5', 'S1'], ['S2', 'S4', 'S5', 'S1']..
你能帮忙纠正一下吗!
您可以使用itertools.groupby
:
from itertools import groupby
lst = ['S1', 'S2', 'S6', 'S1', 'S2', 'S3', 'S4', 'S5', 'S1', 'S2', 'S5', 'S1', 'S2', 'S4', 'S5', 'S1', 'S2', 'S4', 'S5', 'S1', 'S2', 'S3', 'S6']
splitby = 'S1'
res = [[splitby] + list(g) for k, g in groupby(lst, key=lambda x: x != splitby) if k]
# [['S1', 'S2', 'S6'], ['S1', 'S2', 'S3', 'S4', 'S5'], ['S1', 'S2', 'S5'], ['S1', 'S2', 'S4', 'S5'], ['S1', 'S2', 'S4', 'S5'], ['S1', 'S2', 'S3', 'S6']]
你有一个逐一错误。 更改以下行:
idx_list = [idx + 1 for idx, val in
enumerate(steps) if val == 'S1']
到
idx_list = [idx for idx, val in
enumerate(steps) if val == 'S1' and idx > 0]
结果应该是:
[['S1', 'S2', 'S6'], ['S1', 'S2', 'S3', 'S4', 'S5'],
['S1', 'S2', 'S5'], ['S1', 'S2', 'S4', 'S5'],
['S1', 'S2', 'S4', 'S5'], ['S1', 'S2', 'S3', 'S6']]
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