Practice extracting variables

Question

Is better to use $id_name ( Class A Method b() ) OR $id_name_2 ( Class A Method c())?

<?php

Class A { 

    function a(){
        $params = array(
            'id'=> 1,
            'name' => 'b',
        );

        $id_name = $this->b($params);
        $id_name_2 = $this->c($params);
    }

    function b($params){
        $id = $params['id'];
        $name = $params['name'];
        /*******

            Some code performing operations with $name and $id

        ********/

        $str = $id . $name; 
        return $str;
    }


    function c($params){

        /*******

            Some code performing operations with $params['name'] and $params['id']

        ********/

        $str = $params['name'] . $params['id'];

        return $str;
    }

}

Answer 1

Using method c will have an side-effect if $params is modified. This is because arrays are passed by reference, and so any changes to $params will be visible to the caller when the function returns. Use b if you need to manipulate id or name, unless you intend to return the modifications to the caller.

Example:

$params = array('id' => 1, 'name' => 'b');
$this->d($params);
echo $params['id']; // outputs 2
...

function d($params) {
    $params['id']++;
}

Answer 2

You want to be using method B. It will make for more readable code and will lead to less mystery bugs.

One cool PHP trick for extracting an assosiative array into variables is the Extract method.

$params = array(
    'id' => 1,
    'name' => 'foo'
);

extract($params);

echo $name . $id;
//"Foo1"

This makes more sense when you've got more elements, but I've always found it to be a clean way to express what you're trying to do.

The reverse is Compact which is great if you need to convert your values back to their original array form.