1.2.383. Double array_flip()

Avoid double array_flip() to gain speed. While array_flip() alone is usually useful, a double call to array_flip() is made to make values and keys unique.

<?php

// without array_flip
function foo($array, $value) {
    $key = array_search($array, $value);

    if ($key !== false) {
        unset($array[$key]);
    }

    return $array;
}

// double array_flip
// array_flip() usage means that $array's values are all unique
function foo($array, $value) {
    $flipped = array_flip($value);
    unset($flipped[$value]);
    return array_flip($flipped);
}

?>

1.2.383.1. Suggestions

• Use array_unique() or array_count_values().

• Use array_flip() once, and let PHP garbage collect it later.

• Keep the original values in a separate variable.

1.2.383.2. Specs

Short name	Performances/DoubleArrayFlip
Rulesets	All, Changed Behavior, Performances
Exakat since	1.1.4
PHP Version	All
Severity	Major
Time To Fix	Quick (30 mins)
Precision	Very high
Examples	NextCloud
Available in	Entreprise Edition, Exakat Cloud