What exactly does the u modifier in regular expressions from preg_ to PHP ?
Should I use it whenever I process strings that have accented characters?
$valor = 'ãẽi ouã';
preg_match('/\w+/u', $valor, $matches);
$matches; // 'array(2) { ãẽi, ouã}
This /u f modifier is for unicode support.
For example if you want to make a regex with Japanese words you need to use it.
preg_match('/[\x{2460}-\x{2468}]/u', $str);
Where \x{hex} - is a char-code hexadecimal UTF-8.
Running the following regex:
$valor = 'ãẽi ouã';
preg_match('/\w+/u', $valor, $matches);
returns:
array (
0 =>
array (
0 => 'ãẽi',
1 => 'ouã',
),
)
Running the following regex (without the modifier):
$valor = 'ãẽi ouã';
preg_match('/\w+/', $valor, $matches);
returns:
array (
0 =>
array (
0 => '�',
1 => '��',
2 => 'i',
3 => 'ou�',
),
)
Should not be used to get accented vowels examples:
$valor = 'ãẽi ouã';
preg_match('/a/u', $valor, $matches);
returns:
array (
0 =>
array (
),
)
Test site: Link
Documentation: Link