python - 替换所有出现的连续重复值对

Question

我有一个带有重复连续逗号的字符串，我想在逗号之间插入一个字符，例如零。当我运行 re.sub 时，它返回的是:

re.sub(r",,", ",0," , "a,,,,,,,,,,,,,a",)
'a,0,,0,,0,,0,,0,,0,,a'

我想要的结果是所有替换，例如:

'a,0,0,0,0,0,0,0,0,0,0,0,0,a'

我明白为什么会发生这种情况，模式中有重叠，但我不知道如何修复它。

Answer 1

您可以使用前瞻来匹配一个逗号后跟另一个逗号，并将匹配项替换为 ",0"，例如:

>>> re.sub(r",(?=,)", ",0", "a,,,,,,,,,,,,,a")
'a,0,0,0,0,0,0,0,0,0,0,0,0,a'

或者不使用正则表达式:

>>> ",".join(x or "0" for x in "a,,,,,,,,,,,,,a".split(","))
'a,0,0,0,0,0,0,0,0,0,0,0,0,a'