Array filter function in PHP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to filter the array and keep only even numbers.

PHP

<?php
$numbers = [1, 2, 3, 4, 5];
$evens = array_filter($numbers, function($n) {
    return $n [1] 2 === 0;
});
print_r($evens);
?>

Drag options to blanks, or click blank then click option'

A%

B==

C===

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of '%' causes wrong filtering.

Using '+' instead of '%' causes syntax errors.

The modulo operator (%) returns the remainder. Using $n % 2 === 0 checks if a number is even.

2fill in blank

medium

Complete the code to filter the array and keep only strings with length greater than 3.

PHP

<?php
$words = ['cat', 'lion', 'dog', 'elephant'];
$longWords = array_filter($words, function($word) {
    return strlen($word) [1] 3;
});
print_r($longWords);
?>

Drag options to blanks, or click blank then click option'

A==

B>

C===

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' filters shorter words instead.

Using '===' compares type and value, not suitable here.

We want words longer than 3 characters, so use '>' to compare length.

3fill in blank

hard

Fix the error in the code to filter numbers greater than 10.

PHP

<?php
$nums = [5, 12, 8, 20];
$filtered = array_filter($nums, function($num) {
    return $num [1] 10;
});
print_r($filtered);
?>

Drag options to blanks, or click blank then click option'

A<

B=

C==

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=' causes assignment, not comparison.

Using '<' filters smaller numbers.

To filter numbers greater than 10, use the '>' operator.

4fill in blank

hard

Complete the code to filter words starting with letter 'a'.

PHP

<?php
$words = 'apple', 'banana', 'avocado', 'cherry'];
$filtered = array_filter($words, function($word) {
    return $word[0 [1] 'a';
});
print_r($filtered);
?>

Drag options to blanks, or click blank then click option'

A[

B==

C===

D(

Attempts:

3 left

💡 Hint

Common Mistakes

Using parentheses instead of brackets to access characters.

Using '===' might cause issues if types differ.

Use square brackets to get the first character and '==' to compare it to 'a'.

5fill in blank

hard

Fill all three blanks to filter an associative array for values greater than 50.

PHP

<?php
$scores = ['Alice' => 45, 'Bob' => 75, 'Carol' => 60];
$highScores = array_filter($scores, function([1]) {
    return [2] [3] 50;
});
print_r($highScores);
?>

Drag options to blanks, or click blank then click option'

Ascore

B$score

C>

D$value

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable names without $ sign.

Using '<' instead of '>' causes wrong filtering.

The function parameter is '$score', and we compare '$score > 50' to filter values greater than 50.