⁍ 𝐑𝐞𝐠𝐞𝐱 𝐍𝐨𝐭𝐞𝐬

Best Reources:

• Interactive Regex Tutorial
• Best Youtube Tutorial Video
• Learn Regex the easy way
• Best Advice on the Internet

Practice:

• Regex Golf
• regexcrossword.com
• regex101.com
• Hackerrank Regex Practise

𝐄𝐬𝐜𝐚𝐩𝐞 𝐂𝐡𝐚𝐫𝐚𝐜𝐭𝐞𝐫𝐬

You should always escape these characters: .[{()\^|?*+
Backslash is used to escape characters

For Example: 
. - selects everything
\. - matches literal dot

You have to also escape a backslash itself i.e. \\ will result in \

𝐌𝐚𝐭𝐜𝐡𝐞𝐬 𝐂𝐡𝐚𝐫𝐚𝐜𝐭𝐞𝐫𝐬

Key	Meaning
.	Any character except new line
\d	Digit (0-9)
\D	Not a Digit (0-9)
\w	Word Characters (a-z, A-Z, 0-9)
\W	Not a word character
\s	Whitespace (space, tab, newline)
\S	Not Whitespace (space, tab, newline)

𝐀𝐧𝐜𝐡𝐨𝐫𝐬 - 𝐌𝐚𝐭𝐜𝐡𝐞𝐬 𝐯𝐢𝐬𝐢𝐛𝐥𝐞 𝐩𝐨𝐬𝐢𝐭𝐢𝐨𝐧𝐬 𝐛𝐞𝐭𝐰𝐞𝐞𝐧 𝐜𝐡𝐚𝐫𝐚𝐜𝐭𝐞𝐫𝐬

Key	Meaning
\b	Word boundary
\B	Not a word boundary
^	Beginning of a string
$	End of a string

??

Key	Meaning
[ ]	Matches characters in brackets
[^ ]	Matches characters NOT in brackets
|	Either Or
()	Group

𝐐𝐮𝐚𝐧𝐭𝐢𝐟𝐢𝐞𝐫𝐬

Key	Meaning
*	0 or more
+	1 or more
?	0 or one
{3}	exact number
{3,4}	range of numbers (minimum, maximum)

Other notes:

• To exclude a string: ^(?!pattern_to_exclude).*$