Benchmark function usage inside for loop

README.md

Results

Run #	Benchmark 1 (sec)	BenchMark 2 (sec)
1	0.2886860370636	0.16710495948792
2	0.31771802902222	0.16766691207886
3	0.27882695198059	0.17383599281311
4	0.2907509803772	0.17733597755432
5	0.28123903274536	0.17464399337769

Conclustion

Inside loop, function called each iteration, which cause almost x2 degradation of performance.

benchmark1.php

<?php

$start = microtime(true);

$string = 'abcdefghijklmnopqrstuvwxyz';
for ($i = 0; $i < 1000000; $i++) {
    for ($a = 0; $a < strlen($string); $a++) {

    }
}

$end = microtime(true);

echo $end - $start . PHP_EOL;

benchmark2.php

<?php

$start = microtime(true);

$string = 'abcdefghijklmnopqrstuvwxyz';
for ($i = 0; $i < 1000000; $i++) {
    $strlen = strlen($string);
    for ($a = 0; $a < $strlen; $a++) {

    }
}

$end = microtime(true);

echo $end - $start . PHP_EOL;