PHP Array Exercises : Merge two commas separated lists with unique value only

Last update on May 30 2022 11:48:47 (UTC/GMT +8 hours)

PHP Array: Exercise-43 with Solution

Write a PHP script to merge two commas separated lists with unique value only.

Sample Solution:

PHP Code:

<?php
$list1 = "4, 5, 6, 7";
  $list2 = "4, 5, 7, 8";
  // combine both lists with unique values only
  $result = implode("," , array_unique(array_merge(explode(",",$list1),explode(",", $list2))));
  echo $result."\n";
?>

Sample Output:

4, 5, 6, 7, 8

Flowchart:

PHP Code Editor:

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Previous: Write a PHP function to find unique values from multidimensional arrays and flatten them in 0 depth.
Next: Write a PHP a function to remove a specified duplicate entry from an array.

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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