php POST Method syntax

Question

Quick auestion here, is this a correct syntax to insert $i variable in POST ?

for($i=13; $i<25; $i++)
            if($_POST[''.$i.'']=='on')  array_push($requestedParameters, $_POST[''.$i.'']);

I want to do this instead of writing all of them apart. And how is it called so I could search in internet detailed explanation on concatenation?

Answer 1

Syntax wise, it is correct, but the single quotes are unnecessary as you aren't adding anything on to either end of $i - this would be better:

if($_POST[$i] == 'on')
    array_push($requestedParameters, $_POST[$i]);

You should probably check that the key exists as well, since you are using what looks like an arbitrary loop rather than a foreach type array loop construct:

if(isset($_POST[$i]) && $_POST[$i] == 'on')

Answer 2

All you need to do is $_POST[$i] since it is an integer and not a String.

If it was a String, you would only have to do this: $_POST["{$i}"]

Answer 3

it would just be like this.

$_POST[$i]

no need for the quotes in there. you put those quotes when you want to add some kind of text between them.

Answer 4

for($i=13; $i<25; $i++)
            if($_POST[$i]==='on')  array_push($requestedParameters, $_POST[$i]);