Question

I have several variables coming from an array in $POST_[‘array’] i wish to make some kind of loop for example foreach that makes, for every value in the variable a variable name of it and assigns the value for it.

For example if i have

$POST_['name'];
$POST_['last'];
$POST_['age'];
$POST_['sex'];

I want the loop to create each variable from the array inside the $_POST with the name of the variable like the following:

$name = 'John';
$last = 'Doe';
$age = '32';
$sex = 'male';

NOTE – The array is coming from a serialized jquery string that puts together all the variables and values in a form into one big string.

Is this possible?

Answer 1

You don’t need a loop, you want extract:

extract($_POST); // But use caution, see below

##Cautions and best practices

As noted in the comments this forces all parameters in the $_POST array into the current symbol space.

In global space

<?php
extract($_GET);
var_dump($_SERVER); // Can be overwritten by the GET param
?>

The code above illustrates the problem as shown in this answer — some pretty dangerous things can be overwritten in the global space.

Inside a function

function myFunc() {
    // (Mostly) empty symbol space! (excluding super globals)
    extract($_POST);
}

Inside a function, as the first line, no harm done.

Important note: You might think since $_SERVER is a super global, that this exploit could happen inside a function as well. However, in my testing, on PHP Version 5.3.4, it is safe inside a function — neither $_SERVER, $_POST, $_GET, $_SESSION, or presumably other superglobals, could be overwritten.

With options

You can also use extract with extract_type options that do not overwrite.

The best option to use, in my opinion, is simply to prefix all variables from extract:

// $_GET = test=1&name=Joe

extract($_GET, EXTR_PREFIX_ALL, "request_get");

echo $request_get_test; // 1
echo $request_get_name; // Joe

That way you don’t have the overwrite problem, but you also know you got everything from the array.

##Alternate – looping w/ conditional

If you wanted to do this manually (but still dynamically), or wanted to conditionally extract only a few of the variables, you can use variable variables:

foreach ($_POST as $key => $value) {
    if (isset($$key)) continue;

    $$key = $value;
}

(The example condition I’ve used is an overwrite prevention.)