How can I split a string in PHP at the nth occurrence of a needle?

Question

There must be a fast and efficient way to split a (text) string at the "nth" occurrence of a needle, but I cannot find it. There is a fairly full set of functions

Answer 1

I really like Hamze GhaemPanah's answer for its brevity. However, there's a small bug in it.

In the original code:

$i = $pos = 0;
do {
    $pos = strpos($string, $needle, $pos+1);
} while( $i++ < $nth);

$nth in the do while loop should be replaced with ($nth-1) as it will incorrectly iterate one extra time - setting the $pos to the position of the $nth+1 instance of the needle. Here's an example playground to demonstrate. If this link fails here is the code:

$nth = 2;
$string = "44 E conway ave west horse";
$needle = " ";

echo"======= ORIGINAL =======\n";

$i = $pos = 0;
do {
    $pos = strpos($string, $needle, $pos + 1);
} while( $i++ < $nth);

echo "position: $pos \n";
echo substr($string, 0, $pos) . "\n\n";

/*
    Outputs:

    ======= ORIGINAL =======
    position: 11
    44 E conway
*/

echo"======= FIXED =======\n";

$i = $pos = 0;
do {
    $pos = strpos($string, $needle, $pos + 1);
} while( $i++ < ($nth-1) );

echo "position: $pos \n";
echo substr($string, 0, $pos);

/*
    Outputs:

    ======= FIXED =======
    position: 4
    44 E

*/

That is, when searching for the position of the second instance of our needle, our loop iterates one extra time setting $pos to the position of our third instance of our needle. So, when we split the string on the second instance of our needle - as the OP asked - we get the incorrect substring.