Week 4

Notes 4

Simple "/ regex /" 

Regex quick reference
[abc]     A single character: a, b or c
[^abc]     Any single character but a, b, or c
[a-z]     Any single character in the range a-z
[a-zA-Z]     Any single character in the range a-z or A-Z
^     Start of line
$     End of line
\A     Start of string
\z     End of string
.     Any single character
\s     Any whitespace character
\S     Any non-whitespace character
\d     Any digit
\D     Any non-digit
\w     Any word character (letter, number, underscore)
\W     Any non-word character
\b     Any word boundary character
(...)     Capture everything enclosed
(a|b)     a or b
a?     Zero or one of a
a*     Zero or more of a
a+     One or more of a
a{3}     Exactly 3 of a
a{3,}     3 or more of a
a{3,6}     Between 3 and 6 of a

options: i -  case insensitive m make dot match newlines x ignore 
whitespace in regex o perform #{...} substitutions only once

examples w/ preg_match
preg_match("/^[a-zA-Z0-9_]+$/", $string) - returns 1 if $string
  contains only a-z, A-Z, 0-9, or _ for all chars, 0 if not, or 
  false if error occurred.

preg_match("/^[A-Za-z]+$/", $string) - returns 1 if $string
  contains chars A-Za-z

preg_match("/^[\w]+$/", $string) - returns 1 if $string
  contains chars [A-Za-z0-9_]+
  


07/23/2019 at 07:19:50pm