How to match one per line in a regex?

Question

I\'m having a problem with a regex I created. My company searches for errors in an error file and tries to match the file to a set of possible strings. If one of the strings

Answer 1

You can use the parameter count within the re.subn function. This is to indicate the maximum number of replacements to be done.

number_of_errors = re.subn(
    r"(is a duplicate for this vendor|Duplicate transaction detected)", "", string, count = 1)[1]