REG EXP

.       - 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, containing all the world

Quantifiers:

*       - 0 or More

+       - 1 or More

?       - 0 or One

{3}     - Exact Number

{3,4}   - Range of Numbers (Minimum, Maximum)

Sample Regexs

[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+.[a-zA-Z0-9-.]+