re.compile
Compile a regular expression into a pattern object for reuse.
Python 3.13
re.compile(pattern, flags=0)Parameters
- patternstr | Pattern
- The regular expression.
- flagsintoptional
- Flags such as re.IGNORECASE; combine several flags with |.
Return value
A Pattern object with search, match, findall, sub and other methods.
Examples
Finding numbers with a compiled pattern
Python 3.13
import re
prog = re.compile(r'\d+')
print(prog.findall('12 drummers, 11 pipers'))['12', '11']
Pattern with a flag
Python 3.13
import re
word = re.compile(r'python', re.IGNORECASE)
print(word.findall('Python, PYTHON, python'))['Python', 'PYTHON', 'python']
Details
Compiling is useful when one pattern is applied many times. The re module caches recent patterns itself, so it is optional for one-off calls.