Question

I’m attempting to remove something from a string using regex that matches substrings before /../ that either begin at the start or follow a / .

So far I have

re.sub('(?<=[/]|\A).+(?=[/][.][.][/])', '', str)

I keep getting errors though when I attempt this or other variations ranging from it deleting all items after the first / to not deleting the first character of the grouping.

Answer 1

It appears that / itself can never be part of the match. Therefore, try

re.sub(r'[^/]*(?=/\.\./)', '', mystr)

[^/] matches any character that isn’t a /, so it starts matching at the start of the string until it encounters /../, unless there’s a / in-between, in which case the match will start after that.