Filter Values

array_filter keeps only the values accepted by a callback.

filter_values.php

<?php
function is_even($value) {
    return $value % 2 === 0;
}

$extra = ;
$values = [2, $extra, 6];
$kept = array_filter($values, "is_even");
$summary = implode(",", $kept);
$count = count($kept);

echo "extra=" . $extra . "\n";
echo "count=" . $count . "\n";
echo "kept=" . $summary . "\n";

<?php
function is_even($value) {
    return $value % 2 === 0;
}

$extra = ;
$values = [2, $extra, 6];
$kept = array_filter($values, "is_even");
$summary = implode(",", $kept);
$count = count($kept);

echo "extra=" . $extra . "\n";
echo "count=" . $count . "\n";
echo "kept=" . $summary . "\n";

<?php
function is_even($value) {
    return $value % 2 === 0;
}

$extra = ;
$values = [2, $extra, 6];
$kept = array_filter($values, "is_even");
$summary = implode(",", $kept);
$count = count($kept);

echo "extra=" . $extra . "\n";
echo "count=" . $count . "\n";
echo "kept=" . $summary . "\n";

keep matching values Filtering is useful when the callback can answer yes or no for each value.