RegEx stands for the Regular Expressions.
Regex are used to validate for mail, username and debit cards.
Snippets:
Below are snippet for regular expressions for matching code.
. 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)
\b Word Boundary
\B Not a Word Boundary
^ Beginning of a String
$ End of a String
[] Matches Characters in brackets
[^ ] Matches Characters NOT in brackets
| Either Or
( ) Group
Quantifiers:
* 0 or More
+ 1 or More
? 0 or One
{3} Exact Number
{3,4} Range of Numbers (Minimum, Maximum)
Sample Regex:
[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+\.[a-zA-Z0-9-.]+