A guide to most used regular expressions in Python

regex.py

import re

'''
Identifiers:

\d = any number
\D = anything but a number
\s = space
\S = anything but a space
\w = any letter
\W = anything but a letter
. = any character, except for a new line
\b = space around whole words
\. = period. must use backslash, because . normally means any character.
Modifiers:

{1,3} = for digits, u expect 1-3 counts of digits, or "places"
+ = match 1 or more
? = match 0 or 1 repetitions.
* = match 0 or MORE repetitions
$ = matches at the end of string
^ = matches start of a string
| = matches either/or. Example x|y = will match either x or y
[] = range, or "variance"
{x} = expect to see this amount of the preceding code.
{x,y} = expect to see this x-y amounts of the precedng code
White Space Charts:

\n = new line
\s = space
\t = tab
\e = escape
\f = form feed
\r = carriage return
Characters to REMEMBER TO ESCAPE IF USED!

. + * ? [ ] $ ^ ( ) { } | \
Brackets:

[] = quant[ia]tative = will find either quantitative, or quantatative.
[a-z] = return any lowercase letter a-z
[1-5a-qA-Z] = return all numbers 1-5, lowercase letters a-q and uppercase A-Z

Compilation FLAGS
Compilation flags let you modify some aspects of how regualr expressions works.
Flags are available in the re module under two names, a long name such as
IGNORECASE and a short, one-letter form such as I
Flag                      Meaning
ASCII, A                  Makes several escapes like \w, \b, \s and \d
                          match only on ASCII characters with the
                          respective property.
DOTALL, S                 Make . match ant character, including newlines
IGNORECASE, I             Do case-insensitivematches
LOCALE, L                 Do a locale-aware match
MULTILINE, M              Multiline matching, affecting ^ and $
VERBOSE, X(for'extended') Enable verbose REs, which can be organized
                          more cleanly and understandably


MATCH FUNCTION
matchObj = re.match(pattern, string, flags=0)

SEARCH FUNCTION
searchObj = re.search(pattern, string, flags=0)

'''


# search function of re
def search(pattern, string, flags=0):
    try:
        searchObj = re.search(pattern, string, flags)
        
        if searchObj:
            return searchObj.groups()
        else:
            return 'No match found!'
        
    except Exception as e:
        return str(e)


# match function of re
def match(pattern, string, flags=0):
    try:
        matchObj = re.match(pattern, string, flags)
        
        if matchObj:
            return matchObj.groups()
        else:
            return 'No match found!'
        
    except Exception as e:
        return str(e)


# findall function of re
def findall(pattern, string, flags=0):
    try:
        find = re.findall(pattern, string, flags)
        return find
    except Exception as e:
        return str(e)