Uso avanzado de expresiones regulares en PHP
Interesante y completo tutorial en el que se nos explica usos de las expresiones regulares que normalmente no solemos tener en cuenta:
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preg_match("/^
(1[-\s.])? # optional '1-', '1.' or '1'
( \( )? # optional opening parenthesis
\d{3} # the area code
(?(2) \) ) # if there was opening parenthesis, close it
[-\s.]? # followed by '-' or '.' or space
\d{3} # first 3 digits
[-\s.]? # followed by '-' or '.' or space
\d{4} # last 4 digits
$/x",$number);Callbacks
$template = preg_replace_callback('/\[(.*)\]/','my_callback',$template);
function my_callback($matches) {
/* codigo */
}‘Codicia’ de la regexp
$html = 'Hello World!';
// note the ?'s after the *'s
if (preg_match_all('/.*?<\/a>/',$html,$matches)) {
print_r($matches);
} Prefijos y sufijos
$pattern = '/foo(?=bar)/';
$pattern = '/foo(?!bar)/';
$pattern = '/(?Condicionales
// if it begins with 'q', it must begin with 'qu'
// else it must begin with 'f'
$pattern = '/^(?(?=q)qu|f)/';Subpatrones
preg_match('/(?PH.*) (?Pf.*)(?Pb.*)/', 'Hello foobar', $matches);
echo "f* => " . $matches['fstar']; // prints 'f* => foo'
echo "b* => " . $matches['bstar']; // prints 'b* => bar' 