Array search functions in PHP - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the value 5 exists in the array.

PHP

<?php
$numbers = [1, 3, 5, 7];
if (in_array([1], $numbers)) {
    echo "Found!";
} else {
    echo "Not found.";
}
?>

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

A0

B7

C2

D5

Attempts:

3 left

💡 Hint

Common Mistakes

Using a value not present in the array.

Confusing the array variable with the value.

The in_array function checks if a value exists in an array. Here, we want to check for 5.

2fill in blank

medium

Complete the code to find the index of the value 3 in the array.

PHP

<?php
$letters = ['a', 'b', 'c', 'd'];
$index = array_search([1], $letters);
echo $index;

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

A'b'

B'c'

C'a'

D'd'

Attempts:

3 left

💡 Hint

Common Mistakes

Searching for a value not in the array.

Confusing the value with the index.

The array_search function returns the index of the searched value. The value 'b' is at index 1.

3fill in blank

hard

Fix the error in the code to correctly check if the key 'color' exists in the array.

PHP

<?php
$info = ['color' => 'red', 'size' => 'large'];
if (array_key_exists([1], $info)) {
    echo "Key found.";
} else {
    echo "Key not found.";
}
?>

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

A'red'

B'color'

C'size'

D'large'

Attempts:

3 left

💡 Hint

Common Mistakes

Checking for a value instead of a key.

Using the wrong key name.

The array_key_exists function checks if a key exists in an array. The key to check is 'color'.

4fill in blank

hard

Fill both blanks to create an array of keys from the array and check if 'age' is one of them.

PHP

<?php
$user = ['name' => 'Alice', 'age' => 25];
$keys = [1]($user);
if (in_array([2], $keys)) {
    echo "Age key exists.";
} else {
    echo "Age key missing.";
}
?>

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

Aarray_keys

B'age'

C'name'

Darray_values

Attempts:

3 left

💡 Hint

Common Mistakes

Using array_values instead of array_keys.

Checking for a value instead of a key.

array_keys gets all keys from the array. Then in_array checks if 'age' is among those keys.

5fill in blank

hard

Fill all three blanks to find the index of 'blue' in the colors array and print a message if found.

PHP

<?php
$colors = ['red', 'green', 'blue', 'yellow'];
$pos = array_search([1], $colors);
if ($pos !== [2]) {
    echo "Found color at index [3].";
} else {
    echo "Color not found.";
}
?>

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

A'blue'

Bfalse

C$pos

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing with null instead of false.

Printing the wrong variable for the index.

array_search returns the index or false if not found. We check if the result is not false and then print the index.