Ranges
All Ranges are inclusive
- [a-z] ⇒ from a to z lower case only
- [A-Z] ⇒ from A to Z upper case only
- [0-9] ⇒ from 0 to 9
- [a-f] ⇒ from a to f
- [g-p] ⇒ from g to p
- [#$%&@] ⇒ any of those symbols
- [a-zA-Z0-9] ⇒ all digits, lower and upper case letters.
Repeat exact
using the {} curly braces notation
- a{5} ⇒ will match “aaaaa”.
- n{3} ⇒ will match “nnn”.
- [a-z]{4} ⇒ will match any four-letter word such as
- [a-z]{6,} ⇒ will match any word with six or more letters.
- [a-z]{8,11} ⇒ will match any word between eight and 11 letters.
- [0-9]{11} ⇒ will match an 11-digit number.
Generic selectors
- \d ⇒ matches any digit that is the same as [0-9]
- \w ⇒ matches any letter, digit and underscore character
- \s ⇒ matches a whitespace character — that is, a space or tab
- \t ⇒ matches a tab character only
- . ⇒ match any digit, letter or symbol except newline.
Special Characters (nasty ones)
- + ⇒ One or more
- ? ⇒ Zero or one
- * ⇒ Zero or more. It’s like the combination of + and ?.
- \ ⇒ escape character
- [^] ⇒ logical not or except
- | (pipe char) ⇒ logical or
- () ⇒ group together
- ^ ⇒ start of a string.
- $ ⇒ end of the string.