Closures in array functions in PHP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to filter numbers greater than 5 using array_filter and a closure.

PHP

<?php
$numbers = [2, 5, 8, 1, 10];
$filtered = array_filter($numbers, function($num) {
    return $num [1] 5;
});
print_r($filtered);
?>

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

A!=

B<

C==

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '>' will filter numbers less than 5.

Using '==' will only keep numbers equal to 5.

The closure checks if each number is greater than 5 using the '>' operator.

2fill in blank

medium

Complete the code to double each number in the array using array_map and a closure.

PHP

<?php
$numbers = [1, 2, 3, 4];
$doubled = array_map(function($num) {
    return $num [1] 2;
}, $numbers);
print_r($doubled);
?>

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

A+

B/

C*

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using '+' will add 2 instead of doubling.

Using '-' or '/' will not double the number.

The closure multiplies each number by 2 to double it.

3fill in blank

hard

Fix the error in the closure to correctly filter even numbers using array_filter.

PHP

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

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

A%

B/

C*

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using '/' will perform division, not remainder.

Using '*' or '+' will not check for even numbers.

The modulus operator '%' returns the remainder. Checking if $num % 2 == 0 finds even numbers.

4fill in blank

hard

Fill both blanks to create an array of squares for numbers greater than 3 using array_map and array_filter with closures.

PHP

<?php
$numbers = [1, 2, 3, 4, 5];
$filtered = array_filter($numbers, function($num) {
    return $num [1] 3;
});
$squares = array_map(function($num) {
    return $num [2] $num;
}, $filtered);
print_r($squares);
?>

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

A>

B*

C+

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' will filter numbers less than 3.

Using '+' instead of '*' will add numbers instead of squaring.

The first closure filters numbers greater than 3 using '>'. The second closure squares each number by multiplying it by itself using '*'.

5fill in blank

hard

Fill all three blanks to create an associative array with uppercase keys and values filtered by length greater than 4 using closures.

PHP

<?php
$words = ['apple', 'bat', 'carrot', 'dog'];
$result = array_filter(array_combine(array_map(function($word) {
    return [1];
}, $words), $words), function($word) {
    return strlen($word) [2] 4;
});
$result = array_map(function($word) {
    return [3];
}, $result);
print_r($result);
?>

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

Astrtoupper($word)

B>

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' will filter words with length less than or equal to 4.

Not converting keys or values to uppercase will not meet the requirement.

The first blank converts each word to uppercase for keys using strtoupper($word). The second blank filters words with length greater than 4 using '>'. The third blank converts values to uppercase using strtoupper($word).