RE	Description
.	Any character except new line
\d	Digit (0 - 9)
\D	Not a Digit
\w	Word character (a-z, A-Z, 0-9, _)
\W	Not a word character
\s	Whitespace (space, tab, newline)
\S	Not whitespace
\b	Word boundary #\bha means space or nothing before 'ha'
\B	Not a word boundary
^	Beginning of a string
$	End of a string
[]	Matches characters in bracket, no need for inside in case of escape characters,[1-7] == [1234567] != [-17]
[^ ]	Matches characters not in bracket, [^a-c] == all letters except a,b,c
|	Either Or
()	Group
Quantifiers
*	0 or more
+	1 or more
?	0 or 1
{3}	Exact number
{3, 4}	Range of numbers (minimum, maximum)
Meta Characters
.[{()^$?*+	need to be escaped by (back slash)

Text	Regular Expression
abcdefghijklmnopqurtuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 1234567890
Ha HaHa	\bHa (using word boundary)
abhishekpathak.com	\w+\.com
321-555-4321 123.555.1234	\b{3}[-.]\b\{3}[-.]\b{4}
Mr. Schafer Mr Smith Ms David Mrs. Robinson Mr. T	M(r\|s\|rs).?\s[A-Z]\w*
cat mat pat bat	[^b]at
CoreyMSchafer@gmail.com corey.schafer@university.edu corey-321-schafer@my-work.net	[a-zA-Z0-9.-]+@[a-zA-Z-]+.(com\|edu\|net)
All kind of email addresses	[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+

```python

raw string: print("\tTab"): ____Tab ; print(r"\tTab"): \tTab

import re search_in_text = """ abcdefghijklmnopqurtuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ 1234567890 """ pattern = re.compile(r'regular_expression_here') searches = pattern.finditer(search_in_text) for search in searches: print(search)```