Array walk 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_walk.

PHP

<?php
$fruits = ['apple', 'banana', 'cherry'];
function printFruit($item) {
    echo $item . "\n";
}
array_walk($fruits, [1]);
?>

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

AprintFruit

Bprint

Cecho

Darray_map

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'print' or 'echo' directly as the callback causes errors.

Passing 'array_map' instead of a callback function.

The array_walk function requires a callback function name to apply to each element. 'printFruit' is the correct callback.

2fill in blank

medium

Complete the code to modify each element of the array by appending ' fruit' using array_walk.

PHP

<?php
$fruits = ['apple', 'banana', 'cherry'];
function addFruitSuffix(&$item) {
    $item .= [1];
}
array_walk($fruits, 'addFruitSuffix');
print_r($fruits);
?>

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

A' fruit'

B"fruit"

C'fruit'

D" fruit"

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting the space before 'fruit' causes words to join without space.

Using single quotes without space changes output formatting.

Double quotes " fruit" correctly append the string with a space to each element.

3fill in blank

hard

Fix the error in the code to correctly print keys and values using array_walk.

PHP

<?php
$colors = ['red' => '#FF0000', 'green' => '#00FF00', 'blue' => '#0000FF'];
function printColor($value, [1]) {
    echo "$key: $value\n";
}
array_walk($colors, 'printColor');
?>

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

Aindex

Bkey

Citem

Dcolor

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different variable name than 'key' causes undefined variable error.

Swapping the order of parameters causes wrong output.

The second parameter in the callback for array_walk is the key, so it must be named 'key' to match the echo statement.

4fill in blank

hard

Fill both blanks to create an array_walk callback that prints the key and value separated by a colon.

PHP

<?php
$items = ['pen' => 1.5, 'notebook' => 2.0, 'eraser' => 0.5];
function printItem([1], [2]) {
    echo "$key: $value\n";
}
array_walk($items, 'printItem');
?>

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

Avalue

Bitem

Ckey

Dprice

Attempts:

3 left

💡 Hint

Common Mistakes

Reversing the order of parameters.

Using variable names that don't match the echo statement.

The callback parameters must be value first, then key, matching the echo statement variables.

5fill in blank

hard

Fill all three blanks to create a callback that appends the key in parentheses to each value in the array.

PHP

<?php
$animals = ['cat' => 'meow', 'dog' => 'woof', 'cow' => 'moo'];
function appendKeyToValue(&[1], [2]) {
    $[1] .= ' (' . [2] . ')';
}
array_walk($animals, 'appendKeyToValue');
print_r($animals);
?>

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

Asound

Bkey

Cvalue

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong variable names causing undefined variable errors.

Not passing the first parameter by reference.

The first blank is the reference to the value variable 'sound', second is the key 'key', and the third is again the value variable 'sound' to append the key.