To satisfy the requirement that "it needs to be as fast as possible" I ran a benchmark against some possible solutions. Each solution had to satisfy this set of test cases.
$cases = [
'aaa-zzz' => 'zzz',
'zzz' => 'zzz',
'-zzz' => 'zzz',
'aaa-' => '',
'' => '',
'aaa-bbb-ccc-ddd-eee-fff-zzz' => 'zzz',
];
Here are the solutions:
function test_substr($str, $delimiter = '-') {
$idx = strrpos($str, $delimiter);
return $idx === false ? $str : substr($str, $idx + 1);
}
function test_end_index($str, $delimiter = '-') {
$arr = explode($delimiter, $str);
return $arr[count($arr) - 1];
}
function test_end_explode($str, $delimiter = '-') {
$arr = explode($delimiter, $str);
return end($arr);
}
function test_end_preg_split($str, $pattern = '/-/') {
$arr = preg_split($pattern, $str);
return end($arr);
}
Here are the results after each solution was run against the test cases 1,000,000 times:
test_substr : 1.706 sec
test_end_index : 2.131 sec +0.425 sec +25%
test_end_explode : 2.199 sec +0.493 sec +29%
test_end_preg_split : 2.775 sec +1.069 sec +63%
So turns out the fastest of these was using substr
with strpos
. Note that in this solution we must check strpos
for false
so we can return the full string (catering for the zzz
case).