PHP offers numerous methods to find out if a text string contains another substring:
strpos : to find the first occurrence strrpos : to find the last occurrence strstr : to find the first occurrence preg_match : to search using (or not) with regular expressions What are the differences between them (especially strpos and strstr )? Is there one that is faster? Which of them is more advisable or depends on the situation?
As far as functionality is concerned, it would depend on what you would like to find.
For example, let's look for the element "world" within this chain (you can check that I have twice put the word world in the chain):
$string = "jersiojresoiresmundojrepiojreopsijreposijmundorpeosijreoisj";
And we are going to apply the different methods, which look similar, but are not the same:
strpos
echo strpos($string, "mundo"); //Devuelve 15, la POSICIÓN de la primera ocurrencia
strrpos
echo strrpos($string, "mundo"); //Devuelve 41, la POSICIÓN de la última ocurrencia.
strstr
echo strstr($string, "mundo"); //Devuelve "mundojrepiojreopsijreposijmundorpeosijreoisj", es decir, todo el String desde la primera ocurrencia
preg_match
echo preg_match("/mundo/i", $string); //Devuelve 1 ya que ha encontrado la cadena dentro del string. En caso contrario, marcaría un 0
echo preg_match("/casa/i", $string); //Devuelve 0
As to whether it is faster strpos or strstr , as indicated by the PHP documentation for the case of strstr :
If you only want to know if a certain needle appears in a haystack, the strpos () function is used, which is faster and requires less memory.
PHP Benchmark
Test environment:
Test function:
$randomString = 'KWFuPHrOoLzcVMVpTFooczSsXvztgORWRYhApKbMvRFLexLOKLLBarQqUpCCPZiqHipTaK';
//^^^Foo //^^^Bar
$start = microtime(true);
for ($i = 0; $i < 10000000; $i++) { // iteración 10 milliones
// Método
}
echo 'Tiempo: '.number_format(( microtime(true) - $start), 4).' segundos';
Result:
Method: strpos ()
strpos($randomString, 'Foo'); - Tiempo: 0.5009 segundos
strpos($randomString, 'Bar'); - Tiempo: 0.4699 segundos
Method: strrpos ()
strrpos($randomString, 'Foo'); - Tiempo: 0.7650 segundos
strrpos($randomString, 'Bar'); - Tiempo: 0.4894 segundos
Method: strstr ()
strstr($randomString, 'Foo'); - Tiempo: 1.0125 segundos
strstr($randomString, 'Bar'); - Tiempo: 0.9465 segundos
Method: preg_match ()
preg_match('/Foo/', $randomString); - Tiempo: 1.1475 segundos
preg_match('/Bar/', $randomString); - Tiempo: 1.0569 segundos
in-sensitive string matching:
preg_match('/Foo/i', $randomString); - Tiempo: 1.1483 segundos
preg_match('/Bar/i', $randomString); - Tiempo: 1.1304 segundos