arrays - Which is faster: in_array() or a bunch of expressions in PHP?

Question

Is it faster to do the following:

 if ($var != 'test1' && $var != 'test2' && $var != 'test3' && $var != 'test4') { ... }

Or:

 if (!in_array($var, array('test1', 'test2', 'test3', 'test4') { ... }

Is there a number of values at which point it's faster to do one or the other?

(In this case, the array used in the second option doesn't alreay exist.)

Answer 1

i'd strongly suggest just using in_array(), any speed difference would be negligible, but the readability of testing each variable separately is horrible.

just for fun here's a test i ran:

$array = array('test1', 'test2', 'test3', 'test4');
$var = 'test';
$iterations = 1000000;

$start = microtime(true);
for($i = 0; $i < $iterations; ++$i) {
    if ($var != 'test1' && $var != 'test2' && $var != 'test3' && $var != 'test4') {}
}
$end = microtime(true);

print "Time1: ". ($end - $start)."<br />";

$start2 = microtime(true);
for($i = 0; $i < $iterations; ++$i) {
    if (!in_array($var, $array) ) {}
}
$end2 = microtime(true);

print "Time2: ".($end2 - $start2)."<br />";

// Time1: 1.12536692619
// Time2: 1.57462596893

slightly trivial note to watch for, if $var is not set, method 1 takes much longer (depending on how many conditions you test)

Update for newer PHP versions:

Martijn: I'ved extended the array to five elements, and look for test3, as sort of an average case.

PHP5.6

Time1: 0.20484399795532
Time2: 0.29854393005371

PHP7.1

Time1: 0.064045906066895
Time2: 0.056781053543091

PHP7.4

Time1: 0.048759937286377
Time2: 0.049691915512085

PHP8.0

Time1: 0.045055150985718
Time2: 0.049431085586548

Conclusion: The original test wasnt the best test, and also: In php7+ is has become a matter of preference.