1.2.642. Logical To in_array¶
Multiple exclusive comparisons with
or`may be replaced by faster alternative.
isset() and an array which keys are the target comparisons
array_key_exists() and an array which keys are the target comparisons
strpos() call, with all the target values merged into a string
str_contains() call, with all the target values merged into a string
switch() call, with each case being an assignation
match() call
in_array() call, with each values in an array
While each alternative has its performance gain, they make the code more readable by bringing the alternative values into one simple list.
As little as three or comparisons are slower than using an alternative. The more calls, the slower is as string of or. Also, the further the target value is in the or list, the slower it is to find it. Although, it is not easy to control that value.
This analysis also reports in_array() calls with arrays of a single element : those should be turned into a or call, or have more values in the array, or have the array published as a constant.
This is a micro-optimisation : speed gain is low, and marginal. Code centralisation is a more significant advantage.
Thanks to Frederic Bouchery for extending the alternatives of that analysis.
<?php
$targetValues = array('a', 'b', 'c', 'd');
$needle = 'd'; // for example
// isset() & array_key_exists()
$targets = array_flip($targetValues); // This might be a slow operation
isset($targs[$a]);
array_key_exists($a, $targs);
// strpos() & str_contains
$targets = implode('', $targeValues);
strpos($targets, $needle) !== 0
str_contains($targets, $needle) !== 0
// switch()
switch($needle) {
case 'a': // Lots of typing to do
case 'b':
case 'c':
case 'd':
$result = true;
break;
default:
$result = false;
break;
}
// match()
// surprisingly, slitghly slower than switch()
$result = match($needle) {
'a', 'b', 'c', 'd' => true,
default => false
};
// in_array()
// Set the list of alternative in a variable, property or constant.
$result = in_array($a, $valid_values, true); // use third argument when you can
// slowest and hard to read
$result = $a == 'a' || $a == 'b' || $a == 'c' || $a == 'd');
?>
See also in_array(), isset(), match(), switch() and strpos().
1.2.642.1. Suggestions¶
Replace the list of comparisons with a in_array() call on an array filled with the various values
Replace the list of comparisons with a strpos() call on an string joined with the various values
Replace the list of comparisons with a match() call on an string joined with the various values
Replace the list of comparisons with a switch() call on an string joined with the various values
Replace the list of comparisons with a isset() call on a hash whose keys are the various values
1.2.642.2. Specs¶
Short name |
Performances/LogicalToInArray |
Rulesets |
|
Exakat since |
0.12.5 |
PHP Version |
All |
Severity |
Minor |
Time To Fix |
Quick (30 mins) |
Precision |
Very high |
Examples |
|
Available in |