How to check if a string is a valid regex in Python?

Question

In Java, I could use the following function to check if a string is a valid regex (source):

boolean isRegex;
try {
  Pattern.compile(input);
  isRegex = true;
} catch (PatternSyntaxException e) {
  isRegex = false;
}

Is there a Python equivalent of the Pattern.compile() and PatternSyntaxException? If so, what is it?

Asked By: alvas

||

Source

Answer 1

Similar to Java. Use re.error exception:

import re

try:
    re.compile('[')
    is_valid = True
except re.error:
    is_valid = False

exception re.error

Exception raised when a string passed to one of the functions here is
not a valid regular expression (for example, it might contain
unmatched parentheses) or when some other error occurs during
compilation or matching. It is never an error if a string contains no
match for a pattern.

Answered By: falsetru

Answer 2

Another fancy way to write the same answer:

import re
try:
    print(bool(re.compile(input())))
except re.error:
    print('False')

Answered By: Amit Gupta

How to check if a string is a valid regex in Python?

Question:

Answers: