Array search functions in PHP - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this PHP code using array_search?

Consider the following PHP code snippet. What will it output?

PHP

<?php
$array = ['apple', 'banana', 'cherry'];
$pos = array_search('banana', $array);
echo $pos;
?>

A 0

B 1

C 2

D false

💡 Hint

Remember that array_search returns the key of the found element.

The array has 'banana' at index 1, so array_search returns 1.

❓ Predict Output

intermediate

What does array_search return when the element is not found?

What will this PHP code output?

PHP

<?php
$array = ['red', 'green', 'blue'];
$result = array_search('yellow', $array);
var_dump($result);
?>

A bool(false)

B int(0)

C NULL

D string('')

💡 Hint

Check what array_search returns if the value is not found.

array_search returns false if the searched value is not found in the array.

🔧 Debug

advanced

Why does this array_search code produce unexpected output?

Look at this PHP code. It tries to find the key of the value 0 in the array. What is the output and why?

PHP

<?php
$array = [0 => 'zero', 1 => 'one', 2 => 'two'];
$key = array_search(0, $array);
echo $key === false ? 'Not found' : $key;
?>

A 0

B 2

C Not found

D 1

💡 Hint

Check the types of values in the array and what is searched.

The array contains strings, but the search is for integer 0, which is not found, so array_search returns false.

❓ Predict Output

advanced

What is the output when using strict comparison in array_search?

What will this PHP code output?

PHP

<?php
$array = ['1', '2', '3'];
$key = array_search(1, $array, true);
echo $key === false ? 'Not found' : $key;
?>

A Not found

B 1

C 0

D 2

💡 Hint

Strict comparison checks both value and type.

With strict=true, integer 1 is not equal to string '1', so array_search returns false.

🧠 Conceptual

expert

How many elements are in the array after this code?

What is the number of elements in the array after this PHP code runs?

PHP

<?php
$array = ['a' => 1, 'b' => 2, 'c' => 3];
$key = array_search(2, $array);
if ($key !== false) {
    unset($array[$key]);
}
echo count($array);
?>

A 0

B 1

C 3

D 2

💡 Hint

Removing one element reduces the count by one.

array_search finds key 'b', unset removes it, so array has 2 elements left.