PHP Exercises: Create new array from a given array of integers shifting all even numbers before all odd numbers

Last update on May 28 2025 13:07:06 (UTC/GMT +8 hours)

129. Shift Even Numbers Before Odds in Array

Write a PHP program to create new array from a given array of integers shifting all even numbers before all odd numbers.

Sample Solution:

PHP Code :

<?php
// Define a function named 'test' that takes an array of numbers as a parameter
function test($numbers)
{ 
    // Initialize a variable '$index' to keep track of the position of even numbers
    $index = 0;

    // Iterate through the elements of the input array using a for loop
    for ($i = 0; $i < sizeof($numbers); $i++)
    {
        // Check if the current element is an even number
        if ($numbers[$i] % 2 == 0)
        {
            // Swap the current even number with the one at the position indicated by '$index'
            $temp = $numbers[$index];
            $numbers[$index] = $numbers[$i];
            $numbers[$i] = $temp;

            // Increment '$index' to the next position for the next even number
            $index++;
        }
    }

    // Return the modified array with even numbers moved to the front
    return $numbers;
}   

// Call the 'test' function with an example array and store the result in the variable 'result'
$result = test([1, 2, 5, 3, 5, 4, 6, 9, 11]);

// Print the result array as a string
echo "New array: " . implode(',', $result);
?>

Sample Output:

New array: 2,4,6,3,5,1,5,9,11

Flowchart:

For more Practice: Solve these Related Problems:

Write a PHP script to rearrange an array so that all even numbers come before all odd numbers while preserving internal order.
Write a PHP function to partition an array into even and odd elements and then concatenate the two partitions.
Write a PHP program to implement a stable partition algorithm that moves even values to the front of the array.
Write a PHP script to iterate through an array and rebuild it with evens first followed by odds using loops.

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PHP Code Editor:

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