PHP for the Web·PHP from first script to a working app

Arrays and loops

Indexed and associative arrays, filtering and mapping without writing manual loops.

Beginner 14 min read Lesson 4 of 300 Challenge included

What you will be able to do

Use [] for arrays and associative keys for records.
array_filter keeps values whose callback returns true.
array_map transforms every value.
Know that array_filter preserves keys unless you reindex.

In plain English

PHP arrays are ordered maps that can act as lists, dictionaries or both. array_filter and array_map express intent better than a manual loop, and array_column is perfect for pulling one field out of rows.

arrays.phpPHP

<?php
$courses = [
    ['title' => 'HTML', 'minutes' => 12],
    ['title' => 'CSS', 'minutes' => 18],
    ['title' => 'PHP', 'minutes' => 25],
];

$long = array_values(array_filter($courses, fn ($c) => $c['minutes'] >= 18));
$titles = array_column($long, 'title');

print_r($titles);
echo count($courses);

Your turn

Keep only long lessons

Easy

Given an array of minute counts, return a reindexed array containing only values of 15 or more.

PHP · starter

$minutes = [8, 15, 22, 4];

Check your understanding before moving on.

Knowledge checkQuestion 1

What does array_filter return when the callback returns true?

Select an answer to continue

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