PHP Array Exercises : Remove duplicate values from an array which contains only integers or strings

Last update on May 30 2022 11:47:10 (UTC/GMT +8 hours)

PHP Array: Exercise-39 with Solution

Write a PHP program to remove duplicate values from an array which contains only strings or only integers.

Sample Solution:

PHP Code:

<?php
$colors = array( 
  0 => 'Red', 
  1 => 'Green', 
  2 => 'White', 
  3 => 'Black', 
  4 => 'Red', 
); 

$numbers = array( 
  0 => 100, 
  1 => 200, 
  2 => 100, 
  3 => -10, 
  4 => -10, 
  5 => 0, 
); 
$uniq_colors = array_keys(array_flip($colors)); 
$uniq_numbers = array_keys(array_flip($numbers)); 
print_r($uniq_colors);
print_r($uniq_numbers);
?>

Sample Output:

Array                                                       
(                                                           
    [0] => Red                                              
    [1] => Green                                            
    [2] => White                                            
    [3] => Black                                            
)                                                           
Array                                                       
(                                                           
    [0] => 100                                              
    [1] => 200                                              
    [2] => -10                                              
    [3] => 0                                                
)

Flowchart:

PHP Code Editor:

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Previous: Write a PHP function to create a multidimensional unique array for any single key index.
Next: Write a PHP program to get a sorted array without preserving the keys.

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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