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

Python Programming

Question or problem about Python programming:

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

How to solve the problem:

Solution 1:

Similar to Java. Use re.error exception:

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

Solution 2:

Another fancy way to write the same answer:

<em>import re try: print(bool(re.compile(input()))) except re.error: print('False') </em>
<em>import re try: print(bool(re.compile(input()))) except re.error: print('False') </em>
import re try: print(bool(re.compile(input()))) except re.error: print('False') 

Hope this helps!