Test performance of isset, array_key_exists, isset OR array_key_exists on NULL-array item

isset-vs-array_key_exists-vs-both.php

<?php

$a = null;
$key = null;
$startIdx = 0;

$func = function() use (&$a, &$key, &$startIdx) {
    $a = array_fill_keys(range($startIdx, $startIdx+=1000), null);
    $key = $startIdx + 1;
};

$iterations = 10;
$count = 1000000;
$avg = [];

$func();
$name = 'isset';
for ($j = 0; $j < $iterations; ++$j) {
    $start = microtime(true);
    for ($i = 0; $i<$count; ++$i) {
        isset($a[$key]);
    }
    $time = microtime(true) - $start;
    $avg[$name][] = $time;
    echo $name . ': ' . $time . "\n";
}

$func();
$name = 'array_key_exists';
for ($j = 0; $j < $iterations; ++$j) {
    $start = microtime(true);
    for ($i = 0; $i<$count; ++$i) {
        array_key_exists($key, $a);
    }
    $time = microtime(true) - $start;
    $avg[$name][] = $time;
    echo $name . ': ' . $time . "\n";
}

$func();
$name = 'isset || array_key_exists';
for ($j = 0; $j < $iterations; ++$j) {
    $start = microtime(true);
    for ($i = 0; $i<$count; ++$i) {
        isset($a[$key]) || array_key_exists($key, $a);
    }
    $time = microtime(true) - $start;
    $avg[$name][] = $time;
    echo $name . ': ' . $time . "\n";
}

$func();
$a = array_keys($a);
$name = 'in_array';
for ($j = 0; $j < $iterations; ++$j) {

    $start = microtime(true);
    for ($i = 0; $i<$count; ++$i) {
        in_array($key, $a);
    }
    $time = microtime(true) - $start;
    $avg[$name][] = $time;
    echo $name . ': ' . $time . "\n";
}

$func();
$a = array_keys($a);
$name = 'in_array_strict';
for ($j = 0; $j < $iterations; ++$j) {

    $start = microtime(true);
    for ($i = 0; $i<$count; ++$i) {
        in_array($key, $a, true);
    }
    $time = microtime(true) - $start;
    $avg[$name][] = $time;
    echo $name . ': ' . $time . "\n";
}

foreach ($avg as $name => $times) {
    echo $name . ' [AVG]: ' . \array_sum($times)/\count($times) . "\n";
}

PHP 7.0.33-1+ubuntu18.04.1+deb.sury.org+1 (cli) (built: Dec 7 2018 08:28:27) ( NTS )

isset: 0.84976196289062
isset: 0.82834601402283
isset: 0.83587598800659
isset: 0.82731986045837
isset: 0.99396395683289
isset: 1.2600409984589
isset: 1.3517770767212
isset: 1.3481690883636
isset: 1.3409090042114
isset: 1.4142439365387
array_key_exists: 4.1361770629883
array_key_exists: 4.0822560787201
array_key_exists: 4.7288780212402
array_key_exists: 5.2399561405182
array_key_exists: 4.3911950588226
array_key_exists: 4.6153249740601
array_key_exists: 5.1126308441162
array_key_exists: 4.776046037674
array_key_exists: 4.9200160503387
array_key_exists: 4.7212162017822
isset || array_key_exists: 6.5889999866486
isset || array_key_exists: 5.7212750911713
isset || array_key_exists: 5.3783040046692
isset || array_key_exists: 5.3733489513397
isset || array_key_exists: 7.1300749778748
isset || array_key_exists: 6.4987850189209
isset || array_key_exists: 7.5291221141815
isset || array_key_exists: 7.9868159294128
isset || array_key_exists: 7.0143849849701
isset || array_key_exists: 7.2444880008698
isset [AVG]: 1.1050407886505
array_key_exists [AVG]: 4.6723696470261
isset || array_key_exists [AVG]: 6.6465599060059

PHP 7.2.28-3+ubuntu18.04.1+deb.sury.org+1 (cli) (built: Feb 23 2020 07:23:25) ( NTS )
Copyright (c) 1997-2018 The PHP Group
Zend Engine v3.2.0, Copyright (c) 1998-2018 Zend Technologies
    with Zend OPcache v7.2.28-3+ubuntu18.04.1+deb.sury.org+1, Copyright (c) 1999-2018, by Zend Technologies
    with Xdebug v2.9.2, Copyright (c) 2002-2020, by Derick Rethans

isset [AVG]: 0.20750651359558
array_key_exists [AVG]: 0.88147220611572
isset || array_key_exists [AVG]: 0.97458655834198
in_array [AVG]: 5.1713105201721
in_array_strict [AVG]: 9.7148007154465