Question

I am trying to delete all numbers from a string as long as the number ends in ” “,”grams”,”g”,”kg” or “kilograms”.

I am using a regular expression but its not removing any numbers. Whats going wrong?

For example; the string "abc 1231g kjsjk jkdsfkjdkj 11kg" is should produce "abc kjsjk jkdsfkjdkj "

Python code:

from re import sub
test = "abc 1231g kjsjk jkdsfkjdkj 11kg"
test = sub("[\d]+[\sg|$grams|$kg|$kilograms]$"," ",test)
print test # every number is still there

Answer 1

Your regular expression is not capturing what you’re looking for. The square brackets [] indicate defining a character class, so [\sg|$...] isn’t what you want. You should try:

test = sub("\d+(\s|g|grams|kg|kilograms)", " ", test)

Here, we start with \d+ for the number, and then use parentheses () for grouping and put all the possible suffixes in it, separated by |.

To get the output you specified, we need to change a few more things. The replacement string should be "" instead of " ", and we need to be able to pick up an extra space at the end by appending \s? to the regex.

test = sub("\d+(\s|g|grams|kg|kilograms)\s?", "", test)