Regular Expressions
From Logic Wiki
Some Examples
^ : beginning of a line
$ : end of a line
|A : start of a string
|Z : end of a string
. : any character
\w : any letter, digit or underscore
\W : anything that doesn't match \w
\d : any digit
\D : anything not digit
\s : whitespace (space, tab, newline, ...)
\S : non whitespace
* : match zero or more occurances of preceding character and match as many as possible
? : 0 or 1 repetions
* : 0 or more repetions
{n} : \d{1,5} one to 5 chars of decimal
[ ] :Calend[ae]r [a-z] -> a to z [0-9] -> 0 to 9 [A-Fa-t0-4] -> A to F or a to t or 0 to 4]
'(Jennifer|Jen|Jenny)\b\w+\b' -> any Jennifer with a surname
'Je(nnifer|nny\n){1,6}\b\w+\b'
Regex in Ruby
/[aeiou]/ : list of characters
/[A-Z]/ : capital letters
String#match
The String#match method converts a pattern to a Regexp (if it isn‘t already one), and then invokes its match method on the target String object. Here is how you find the characters from a String which are next to a whitespace:
'RubyMonk Is Pretty Brilliant'.match(/ ./)
