How do I split a string and keep the separators using python re library?

Question

Here is my code:

import re
string = r"('Option A' | 'Option B') & ('Option C' | 'Option D')"
word_list = re.split(r"[\(.\)]", string)
-> ['', "'Option A' | 'Option B'", ' & ', "'Option C' | 'Option D'", '']

I want the following result:

-> ["('Option A' | 'Option B')", ' & ', "('Option C' | 'Option D')"]

Answer 1

You can use re.findall to capture each parenthesis group:

import re
string = r"('Option A' | 'Option B') & ('Option C' | 'Option D')"
pattern = r"(\([^\)]+\))"
re.findall(pattern, string)
# ["('Option A' | 'Option B')", "('Option C' | 'Option D')"]

This also works with re.split

re.split(pattern, string)
# ['', "('Option A' | 'Option B')", ' & ', "('Option C' | 'Option D')", '']

If you want to remove empty elements from using re.split you can:

[s for s in re.split(pattern, string) if s]
# ["('Option A' | 'Option B')", ' & ', "('Option C' | 'Option D')"]

---

How the pattern works:

• ( begin capture group
• \( matches the character ( literally
• [^\)]+ Match between one and unlimited characters that are not )
• \) matches the character ) literally
• ) end capture group