如何使用正则表达式替换一些括号而不是其他括号

Question

As the title says, I am trying to replace parentheses with brackets conditionally. For example, I will have a string like:

"(This is some text) but I also have (1) character and not (22) character." The character may be 1 but it could be any singe character.

I only want to replace the text that has one character in it. So the above example will be:

"(This is some text) but I also have [ 1 ] character and not (22) character."

I have tried using this regex which almost works but I can't get text to remain inside:

re.sub("\(.\)", "\[.\]", a)

Edit: Added clarity that it could be any single character within the parentheseses

Answer 1

Use a capture group:

inp = "(This is some text) but I also have (1) character and not (22) character."
output = re.sub(r'\((.)\)', r'[\1]', inp)
print(output)

This prints:

(This is some text) but I also have [1] character and not (22) character.

Answer 2

See this :

>>> x = '(This is some text) but I also have (1) character and not (22) character.'
>>> re.sub('\((.)\)', '[\g<1>]', x)
'(This is some text) but I also have [1] character and not (22) character.'

You need to capture this one character and then use the capture group number to retrieve it.

Answer 3

use {} to control how many characters is your target.

re.sub(r"\((.{1})\)", r"[\1]", a)