import re
# Compile a regular expression pattern into a regular expression object, which can be used for matching using its match(), search() and other methods, described below.
prog = re.compile(pattern)
result = prog.match(string)
# is equivalent to
result = re.match(pattern, string)import re
# regex for finding mentions in a tweet
regex = r"(?<!RT\s)@\S+"
tweet = '@tony I am so over @got and @sarah is dead to me.'
# mentions = ['@tony', '@got', '@sarah']
mentions = re.findall(regex, tweet)
## Search for pattern 'bb' in string 'aabbcc'.
## All of the pattern must match, but it may appear anywhere.
## On success, match.group() is matched text.
match = re.search(r'bb', 'aabbcc') # found, match.group() == "bb"
match = re.search(r'cd', 'aabbcc') # not found, match == None
## . = any char but \n
match = re.search(r'...c', 'aabbcc') # found, match.group() == "abbc"
## \d = digit char, \w = word char
match = re.search(r'\d\d\d', 'p123g') # found, match.group() == "123"
match = re.search(r'\w\w\w', '@@abcd!!') # found, match.group() == "abc"# A Python program to demonstrate working of findall()
import re
# A sample text string where regular expression is searched.
string = """Todays date is 27 , month is 05 and year is 2022"""
# A sample regular expression to find digits.
regex = '\d+'
match = re.findall(regex, string)
print(match)