1.2.998. Processing Collector

When accumulating data in a variable, within a loop, it is slow to apply repeatedly a function to the variable.

The example below illustrate the problem : $collector is build with element from $array. $collector actually gets larger and larger, slowing the in_array() call each time.

It is better to apply the preg_replace() to $a, a short variable, and then, add $a to the collector.

<?php

// Fast way
$collector = '';
foreach($array as $a){
    $a = preg_replace('/__(.*?)__/', '<b>$1</b>', $a);
    $collector .= $a;
}

// Slow way
$collector = '';
foreach($array as $a){
    $collector .= $a;
    $collector = preg_replace('/__(.*?)__/', '<b>$1</b>', $collector);
}

?>

1.2.998.1. Suggestions

• Avoid applying the checks on the whole data, rather on the diff only.

1.2.998.2. Specs

Short name	Performances/RegexOnCollector
Rulesets	All, Changed Behavior, Performances
Exakat since	1.2.4
PHP Version	All
Severity	Minor
Time To Fix	Slow (1 hour)
Precision	Very high
Available in	Entreprise Edition, Exakat Cloud