PHP Variables made with foreach

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.)

Answer 2

Try not to use extract() when using $_POST. You may overwrite variables you want which will result in unpredictable behaviour. It is a bad habit to get into and while is dynamic may not be the best solution.

You can do something like this:

foreach($_POST as $key => $value)
{
    switch($key)
    {
        case "name":
            $name = $value;
        break;
        case "last":
            $last = $value;
        break;
    }
}

Answer 3

You can actually use the built-in function called extract

Answer 4

Why not use a foreach?

foreach($_POST as $key=>$val){
    ${$key} = $val;
}

Answer 5

I just want to mention that you can improve foreach technique because we have in HTML the ability to name one of our form fields using square bracket notation, and if we do that, what HTML will do is it will submit a series of values as an array.

<input name="user[name]">
<input name="user[last]">
<input name="user[age]">
<input name="user[sex]">

Than use just one line of code to assign all values from input fields into local array $args.

$args = $_POST['user'];

So what that means is when we go to process the form, we're looking at an array of values instead of a bunch of single values that we have to go retrieve.

So we can just simply go to the post super global and ask for one item: that is user. And what we get back is an associative array. So instead of having to build up that array by going and retrieving all those values one at a time, we're instantly given an array, just because we named our form fields differently.