Call class method by string name as callback of a native function within another class method [duplicate]

Question

I know this question has been asked before, but not in this context (OOP):

class XYZ {

    public function index() {

        $array = [
            [
                'id' => 1,
                'name' => 'Alpha'
            ],
            [
                'id' => 2,
                'name' => 'Beta'
            ],
            [
                'id' => 3,
                'name' => 'Gamma'
            ]
        ];

        $newArray = usort($array, 'modify');

        return $newArray;

    }

    public function modify($a, $b) {

        return $b['name'] - $a['name'];

    }

}

This indexAction returns an empty array, and I am not sure why.

This is a multi-problem page that probably won't serve as a good signpost to other pages. How to use a class method as a callback is well covered and the common misconception that sorting functions return a useful payload is also well covered. I'll support the deletion of this page as the answers are not high value either. — mickmackusa
– mickmackusa ♦, Commented Jan 23, 2024 at 7:39

Gowtham Raj · Accepted Answer · 2015-09-23 10:42:07Z

3

ksort — Sort an array by key

bool ksort ( array &$array [, int $sort_flags = SORT_REGULAR ] )

Sorts an array by key, maintaining key to data correlations. This is useful mainly for associative arrays.

<?php
$fruits = array("d"=>"lemon", "a"=>"orange", "b"=>"banana", "c"=>"apple");
ksort($fruits);
foreach ($fruits as $key => $val) {
    echo "$key = $val\n";
}
?>

The above example will output:

a = orange b = banana c = apple d = lemon

For more info : http://php.net/manual/en/function.ksort.php

answered Sep 23, 2015 at 10:42

Gowtham Raj

2,9551 gold badge27 silver badges38 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

mickmackusa Over a year ago

This answer appears to completely ignore the asked question. This answer's score is perplexing.

Narendrasingh Sisodia · Accepted Answer · 2015-09-23 13:50:28Z

1

Over here within your usort function the second parameter consist of two values first one ClassName and the other one functionName so your second parameter looks like as

usort($array,['ClassName','functionName']);

Which in your case it'll be like as

usort($array,['XYZ','modify']);

Demo

edited Sep 23, 2015 at 13:50

answered Sep 23, 2015 at 13:05

Narendrasingh Sisodia

21.4k6 gold badges51 silver badges54 bronze badges

Comments

Amarnasan · Accepted Answer · 2015-09-23 10:27:11Z

1

Because usort returns a boolean http://php.net/manual/en/function.usort.php . You want to return the modified variable $array

answered Sep 23, 2015 at 10:27

Amarnasan

15.7k7 gold badges35 silver badges38 bronze badges

1 Comment

Amarnasan Over a year ago

If you want your code to run, please change the question to "Please fix my code so that it works". I answered the current question.

Collectives™ on Stack Overflow

Call class method by string name as callback of a native function within another class method [duplicate]

3 Answers 3

1 Comment

Comments

1 Comment

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

1 Comment

Comments

1 Comment

Linked

Related