通過列表理解修改列表中的列表

Question

如何獲得這些loops以及if statements的理解力？

raw = [['-', 'bla'], ['-', 'la'], ['=', 'bla']]

for one in raw:
    if one[0] == '-':
        for two in raw:
            if two[1] == one[1] and two[0] == '=': two[0] = '--'

至今：

[two+one for two in raw for one in raw]

但不確定將if語句放在哪里：

if one[0] == '-'並且if two[1] == one[1] and two[0] == '=': two[0] = '--'

Answer 1

一個簡單的列表理解就足夠了：

raw = [['-', 'bla'], ['-', 'la'], ['=', 'bla']]

res = [['--' if (i != '-') and (['-', j] in raw) else i, j] for i, j in raw]

結果：

[['-', 'bla'], ['-', 'la'], ['--', 'bla']]

Answer 2

您可以在列表理解中設置項目，

您的代碼：

for one in raw:
    if one[0] == '-':
        for two in raw:
            if two[1] == one[1] and two[0] == '=': two[0] = '--'

轉換為列表理解：

[[two.__setitem__(0,'--') if two[1]==one[1] and two[0]=='=' else two for two in raw] if one[0]=='-' else one for one in raw]
print(raw)

輸出：

[['-', 'bla'], ['-', 'la'], ['--', 'bla']]