preg_match whitespace problem - php

Question

I need to write a regex but for some reason i cannot get the \s to find whitespace,
Im trying....
$name = "a ";
if( preg_match('^[a-z]+\s$', $name)){
echo "match";
} else {
echo "no match";
}
ive also tried
preg_match('^[a-z\s]+$');
and
preg_match('^[a-z]/\s/$');
Im just getting no match.
The full regex needs to allow 1 or more lowercase letters then a space then an uppercase letter followed by one or more lowercase, but....
preg_match('^[a-z]+\s[A-Z][a-z]+$');
isnt working as i'd expect it to going of the tutorials ive seen around the web (sitepoint etc...).
Anyone shed any light on it?

Answer 1

You have to add delimiters(docs) to the expressions:
$name = "a ";
if( preg_match('/^[a-z]+\s$/', $name)){
// ^ ^
// └----------┴----- here: slash as delimiter
echo "match";
} else {
echo "no match";
}
Here I used a slash / but you are pretty much free in choosing a delimiter (ok, not that much: any non-alphanumeric, non-backslash, non-whitespace character).
Make sure you have error reporting set to include warnings, e.g. by adding error_reporting(E_ALL). Then you would have seen this warning:
Warning: preg_match(): No ending delimiter '^' found in ... on line ...
no match
PHP treats the first character in the string as delimiter, so in your case the ^.