Array map function in PHP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to apply a function to each element of the array using array_map.

PHP

<?php
$numbers = [1, 2, 3, 4];
$squared = array_map([1], $numbers);
print_r($squared);
?>

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

Afn($n) => $n * $n

Bfunction square($n) { return $n + 1; }

Carray_sum

Dcount

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function that does not return the squared value.

Passing a function name as a string without defining it.

The array_map function applies the given function to each element of the array. Here, the arrow function fn($n) => $n * $n squares each number.

2fill in blank

medium

Complete the code to convert all strings in the array to uppercase using array_map.

PHP

<?php
$words = ['apple', 'banana', 'cherry'];
$uppercased = array_map([1], $words);
print_r($uppercased);
?>

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

Astrtoupper

Btrim

Cstrlen

Dstrtolower

Attempts:

3 left

💡 Hint

Common Mistakes

Using strtolower which converts to lowercase instead.

Using strlen which returns string length, not the string itself.

The strtoupper function converts strings to uppercase. Using it with array_map applies this to each element.

3fill in blank

hard

Fix the error in the code to correctly double each number in the array using array_map.

PHP

<?php
$nums = [2, 4, 6];
$doubled = array_map([1], $nums);
print_r($doubled);
?>

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

Afunction($x) { return $x * 3; }

Bfunction double($x) { return $x + 2; }

Cfn($x) => $x * 2

Darray_sum

Attempts:

3 left

💡 Hint

Common Mistakes

Using a function that triples the number instead of doubling.

Using a function that adds 2 instead of multiplying.

The arrow function fn($x) => $x * 2 correctly doubles each number. Other options either triple, add 2, or are invalid here.

4fill in blank

hard

Fill both blanks to create an array mapping each word to its length, but only for words longer than 3 characters.

PHP

<?php
$words = ['cat', 'elephant', 'dog', 'giraffe'];
$lengths = array_map([1], array_filter($words, fn($word) => strlen($word) [2] 3));
print_r($lengths);
?>

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

Astrlen

B<=

C>

Dcount

Attempts:

3 left

💡 Hint

Common Mistakes

Using <= instead of > in the filter condition.

Using count instead of strlen for string length.

The array_filter keeps words with length greater than 3 using strlen($word) > 3. Then array_map applies strlen to get their lengths.

5fill in blank

hard

Fill both blanks to create an array of uppercase words that have length less than 6.

PHP

<?php
$words = ['apple', 'banana', 'pear', 'kiwi', 'grape'];
$result = array_map([1], array_filter($words, fn($word) => strlen($word) [2] 6));
print_r($result);
?>

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

Astrtoupper

B<

C<=

Dstrtolower

Attempts:

3 left

💡 Hint

Common Mistakes

Using strtolower instead of strtoupper.

Using <= instead of < in the filter condition.

The array_filter keeps words with length less than 6 using strlen($word) < 6. Then array_map applies strtoupper to convert them to uppercase.