PHP Array Exercises : Sort a specified array by the day and username

Last update on May 30 2022 11:45:14 (UTC/GMT +8 hours)

PHP Array: Exercise-22 with Solution

Write a PHP script to sort the following array by the day (page_id) and username.

Sample Solution:

PHP Code:

<?php
$arra[0]["transaction_id"] = "2025731470"; 
$arra[1]["transaction_id"] = "2025731450"; 
$arra[2]["transaction_id"] = "1025731456"; 
$arra[3]["transaction_id"] = "1025731460"; 
$arra[0]["user_name"] = "Sana"; 
$arra[1]["user_name"] = "Illiya"; 
$arra[2]["user_name"] = "Robin"; 
$arra[3]["user_name"] = "Samantha"; 

//convert timestamp to date 
function convert_timestamp($timestamp){ 
    $limit=date("U"); 
    $limiting=$timestamp-$limit; 
    return date ("Ymd", mktime (0,0,$limiting)); 
} 
//comparison function 
function cmp ($a, $b) { 
    $l=convert_timestamp($a["transaction_id"]); 
    $k=convert_timestamp($b["transaction_id"]); 
    if($k==$l){ 
        return strcmp($a["user_name"], $b["user_name"]); 
    }else{ 
        return strcmp($k, $l); 
    } 
} 
//sort array 
usort($arra, "cmp"); 

//print sorted info 
while (list ($key, $value) = each ($arra)) { 
    echo "\$arra[$key]: "; 
    echo $value["transaction_id"]; 
    echo " user_name: "; 
    echo $value["user_name"]; 
    echo "\n"; 
} 
?>

Sample Output:

$arra[0]: 2025731450 user_name: Illiya                      
$arra[1]: 2025731470 user_name: Sana                        
$arra[2]: 1025731456 user_name: Robin                       
$arra[3]: 1025731460 user_name: Samantha

Flowchart:

PHP Code Editor:

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Previous: Write a PHP function to sort subnets.
Next: Write a PHP program to sort a multi-dimensional array set by a specific key.

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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