PHP Array Exercises : Merge two arrays

Last update on May 30 2022 11:45:04 (UTC/GMT +8 hours)

PHP Array: Exercise-11 with Solution

Write a PHP program to merge (by index) the following two arrays.

Sample arrays :
$array1 = array(array(77, 87), array(23, 45));
$array2 = array("w3resource", "com");

Sample Solution:

PHP Code:

<?php
$array1 = array(array(77, 87), array(23, 45));
$array2 = array("w3resource", "com");
function merge_arrays_by_index($x, $y)
{
$temp = array(); $temp[] = $x; if(is_scalar($y))
{
$temp[] = $y;
}
else
{
foreach($y as $k => $v)
{
$temp[] = $v;
}
}
return $temp;
}
echo '<pre>'; print_r(array_map('merge_arrays_by_index',$array2, $array1));
?>

Sample Output:

<pre>Array                                                  
(                                                           
    [0] => Array                                            
        (                                                   
            [0] => w3resource                               
            [1] => 77                                       
            [2] => 87                                       
        )                                                   
                                                            
    [1] => Array                                            
        (                                                   
            [0] => com                                      
            [1] => 23                                       
            [2] => 45                                       
        )                                                   
                                                            
)

Flowchart:

PHP Code Editor:

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Previous: Write a PHP program to sort an array of positive integers using the Bead-Sort Algorithm.
Next: Write a PHP function to change the specified array's all values to upper or lower case.

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.

PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

Example:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

Ref : https://bit.ly/3i77vCC