How to get value of "string"?

Given strings like:

"hello"
'hello'

I want to remove only first and last char if:

1. They are the same
2. They are " or '

I.e., given 'hello' I’m expecting hello. Given 'hello" I’m not expecting it to change.

I was able to do this by reading first char and last char, validating they are the same + validating they are equal to ' or " and validating it’s not the the same index for char (because I don’t want this: ' to end up as the empty string). With all edge cases checking I ended with 10s of lines.

What’s your approach to solve this?

In simple words, Given a string in Python format I want to return its data and if it’s not valid to keep it as is.

>Solution :

Sounds like a job for regular expressions with groups:

import re
re.sub(r'^([\'"])(.*)(\1)$', r'\2', s)

Which reads as:

• ^ – match the beginning of the string
• (['"]) – either single or double quote (group 1)
• (.*) any (possibly, empty) sequence of characters in between (group 2)
• (\1) – the same character as in group 1
• $ – end of the string

If the string matches the pattern above, replace it with the content of the group 2.

For example:

>>> s = re.sub(r'^([\'"])(.*)(\1)$', r'\2', "'hello'")
>>> print(s)
hello

An alternative way could be with ast.literal_eval(), but it won’t handle non-matching quotes.