5.6. Regexp Compile

5.6.1. About

• re.compile()

• Used when pattern is reused (especially in the loop)

5.6.2. Examples

Compiles at every loop iteration, and then matches:

import re


PATTERN = r'^[a-zA-Z0-9][\w.+-]*@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]{2,}$'
DATA = ['mark.watney@nasa.gov',
        'Mark.Watney@nasa.gov',
        '+mark.watney@nasa.gov',
        'mark.watney+@nasa.gov',
        'mark.watney+newsletter@nasa.gov',
        'mark.watney@.gov',
        '@nasa.gov',
        'mark.watney@nasa.g']

for email in DATA:
    re.match(PATTERN, email)

Compiling before loop, hence matching only inside:

import re


PATTERN = re.compile(r'^[a-zA-Z0-9][\w.+-]*@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]{2,}$')
DATA = ['mark.watney@nasa.gov',
        'Mark.Watney@nasa.gov',
        '+mark.watney@nasa.gov',
        'mark.watney+@nasa.gov',
        'mark.watney+newsletter@nasa.gov',
        'mark.watney@.gov',
        '@nasa.gov',
        'mark.watney@nasa.g']

for email in DATA:
    PATTERN.match(email)