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PHP Enhancing a Simple PHP Application Refactoring the Codebase Separating Concerns: MVC

Welby Obeng
Welby Obeng
20,340 Points
Posted by Welby Obeng
Welby Obeng
20,340 Points

explain this function line by line

Can someone explain this function line by line please

// This function receives a number as an argument.
// It returns the most popular flavors based on
// the number of likes, the most popular flavor
// first. (The number of flavors returned corresponds
// to the number in the argument.)

function get_flavors_by_likes($number) {

    $all = get_all_flavors();

    $total_flavors = count($all);
    $position = 0;

    $popular = $all;
    usort($popular, function($a, $b) {
        return $b['likes'] - $a['likes'];
    });

    return array_slice($popular, 0, $number);

}

?>

1 Answer

Daniel Leak
Daniel Leak
4,105 Points
Daniel Leak
Daniel Leak
4,105 Points

I found usort pretty confusing. First comment on this page explains it fairly well. First variable stores the array by calling outside function. $total_flavors and $position don't even get used, they shouldn't be there. $popular is also not needed, we could get rid of it and replace it's other uses in the code with $all. We only need this

function get_flavors_by_likes($number) {   
//Define function, argument is how many flavors to display

    $all = get_all_flavors();    
//Calls a previous function to assign $flavors array to $all

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

usort will compare each item in the array $all, each time an item is compared to another they will be assigned $a or $b. If the function ($b["likes"]-$a["likes"]) returns a positive number, $b will move 1 towards the top of the array, if negative it will move down and if 0 it will stay in that place. In this case when $b is a larger number than $a, it will be moved to the top of the array and we will have a descending list.

    return array_slice($all, 0, $number);
}

aray_slice displays from the array ($all), starting at the first item in the array(0), however many items we asked for in the functions argument ($number)*/