Some people just like to write as few line of codes as possible. Well, PHP can be tricky sometimes.. For instance, be carefull when declaring a variable and passing it as a parameter to a function or to a method at the same time. If that parameter is supposed to be passed by reference, you may end up with some unexpected behaviors !

Look at the following code, What do you think will be outputted ?

function changeStr(&$str)
{
    $str = 'foo_' . $str;
    return $str;
}

$res = changeStr($str = 'bar');

var_dump($str);
var_dump($res);

Here is the result.

string 'bar' (length=3)
string 'foo_bar' (length=7)

Surprise ! $str didn’t get passed as a reference.

So basically, $str hasn’t been affected by the changeStr() function. Let’s try with an array now..

function changeArr(&$arr)
{
    $arr['id'] = 10;
    return $arr;
}

$res = changeArr($arr = array());

var_dump($arr['id']);
var_dump($res['id']);

The result is…

null
int 10

Well, same behavior as earlier. $arr wasn’t altered by the changeArr() function !

What about objects, does it do the same thing ?

function changeObj(&$obj)
{
    $obj->id = 10;
    return $obj;
}

$res = changeObj($obj = new StdClass());

var_dump($obj->id);
var_dump($res->id);

Here is the result.

int 10
int 10

So, it doesn’t work for a string or an array, but it work with objects !

Well, I highly suggest any developer not to declare a variable and pass it to a method or a function at the same time. Just write the additional line of code, it is gonna reduce the risk of error and actually might make your core more readable !

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