PHP Questions and Answers – Arrays – Part 3

This collection of PHP Multiple Choice Questions and Answers (MCQs): Quizzes & Practice Tests with Answer focuses on “PHP Arrays”.
 

1. Which of the following built-in functions is used to check if the specified key exists in the array?

A arrays_key_exists()

B array_keys_exists()

C array_key_exists()

D array_key_exist()

<?php
    $arr = array("A" => "Alex", "B" => "Bob", "E" => "Emily");
    
    if (array_key_exists("B", $arr))
    {
      echo "Key exists!";
    }
    else
    {
      echo "Key does not exist!";
    }
?>

Key exists!

2. If we transfer arrays by value to a read-only function is it decreasing the performance of execution in comparison with transferring them by reference?

A Yes, since the interpreter needs constantly to create a copy of the array before transfer it to the function.

B Yes, but only if the function changes the array values.

C Yes, but only if the array is big.

D Yes, since PHP should monitor the execution of the function to determine if changes are made to the array.

E No.

3. Which of the following built-in functions is used to compute the difference of arrays?

A arrays_dif()

B diff_array()

C array_diff()

D dif_arrays()

<?php
    $arr1 = array("A"=>"Alex", "B"=>"Bob", "E"=>"Emily");
    $arr2 = array("L"=>"Alex", "O"=>"Bob");
    
    $diff = array_diff($arr1, $arr2);
    print_r($diff);
?>

Array
(
    [E] => Emily
)

4. Suppose you want to sort an array in ascending order by value while keeping key associations. Which of the following built-in functions would you use?

A sort()

B usort()

C krsort()

D asort()

E ksort()

<?php
    $age = array("Alex"=>"50", "Bob"=>"28", "Emily"=>"18");
    asort($age);
?>

Array
(
    [Emily] => 18
    [Bob] => 28
    [Alex] => 50
)

5. Which of the following built-in functions is used to count elements in an array?

A Count_array

B Array_Count

C Sizeof

D count

<?php
    $names = array("Alex", "Bob", "Emily");
    echo sizeof($names);
    echo "\n";
    echo count($names);
?>

3
3

6. What is the result of the following PHP code?

<?php
    $arr1 = array("A"=>"Alex", "B"=>"Bob", "E"=>"Emily");
    $arr2 = array("L"=>"Alex", "O"=>"Bob");
    
    $result = array_intersect($arr1, $arr2);
    print_r($result);
?>

A Array([A] => Alex, [B] => Bob)

B Array([L] => Alex, [O] => Bob)

C Array([E] => Emily)

D Array()

7. What is the result of the following PHP code?

<?php
    $arr = array(2, 1, 3);
    echo(array_product($arr));
?>

A 3

B 2

C 6

D 1

8. What is the result of the following PHP code?

<?php
    $arr1 = array("A", "B");
    $arr2 = array("C", "D");
    $arr3 = array_replace($arr1, $arr2);
    print_r($arr3);
?>

A Array([0] => C, [1] => D)

B Array([0] => A, [1] => B)

C Array([0] => A, [1] => D)

D Array([0] => C, [1] => B)

9. What is the result of the following PHP code?

<?php
    $arr = array("A", "B", "C", "D");
    echo pos($arr);
?>

A D

B A

C 0

D True

10. What is the result of the following PHP code?

<?php
    $nbr = range(0, 2);
    print_r ($nbr);
?>

A Array([0] => 0, [1] => 1, [2] => 2)

B Array([1] => 1, [2] => 2)

C Array([0] => 0, [1] => 1)

D None of the above

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