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.