Pandas - Induce an opening/closing bracket or induce a Negative sign before the number

Question

I have a column which has data with circular braces missing at times: The output required is to either remove the braces and induce a negative sign before the number or add star

Answer 1

You want to add a - before any number that is enclosed with at least one parenthesis on either left, or right, or on both sides.

Use an alternation-based regex:

df['testz'].str.replace(r'\(?\s*(\d+(?:,\d+)?)\s*\)|\(\s*(\d+(?:,\d+)?)\s*\)?', r'-\1\2')

See the regex demo

Details

• \(?\s*(\d+(?:,\d+)?)\s*\) - an optional (, 0+ whitespaces, Group 1: 1+ digits followed with an optional sequence of , and 1+ digits; then 0+ whitespaces and a ) char
• | - or
• \(\s*(\d+(?:,\d+)?)\s*\)? - a ( char, 0+ whitespaces, Group 1: 1+ digits followed with an optional sequence of , and 1+ digits; then 0+ whitespaces and an optional ) char