JAVASCRIPT

regex match number

For matching an integer number of one single char/digit, specify:
[0-9]
But for matching any number of more than one char/digit; add "+":
[0-9]+
Example for matching hour with minutes of HH:MM format in a file:
grep "[0-9]+:[0-9]+" file.txt

regex for numbers

Regex regex = new Regex(@"^d$");

regex number

/[A-Z]/  : 'must contain one uppercase'

/([a-z])/  : 'must contain one lowercase'

/(d)/  : 'must contain one number'

/(W)/  : 'must contain one special character'