Regular Expression

Learn Regex in a easy way

Practice:

• Regex Golf
• regexcrossword.com
• regex101.com

Quick Notes

MetaCharacters (Need to be escaped):
.[{()\^|?*+


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

- You have to escape \ with \ i.e. \\

Matches characters
.  - Any Character Except New Line
\d - Digit (0-9)
\D - Not a Digit (0-9)
\w - Word Character (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
\b - Word Boundary
\B - Not a Word Boundary
^  - Beginning of a String
$  - End of a String

[]   - Matches Characters in brackets
[^ ] - Matches Characters NOT in bracket
|    - Either Or
( )  - Group

Quantifiers:
*      - 0 or More
+      - 1 or More
?      - 0 or One
{3}    - Exact Number
{3, 4} - Range of Numbers (Minimum, Maximum)