Rename posted fields into PHP variables

Question

I have a form with dynamic fields. with inputs with Names like this:

<input type="hidden" name="nome_prod1" value="Shampoo Hidratante Dazen Elegance">
<input data-theme="b" value="0" name="qtd1" type="text" id="1"/>

<input type="hidden" name="nome_prod2" value="Shampoo Hidratante Dazen Elegance">
<input data-theme="b" value="0" name="qtd2" type="text" id="1"/>

each one with its value, the problem is at the time of showing this because did not want to show so little save in the bank the fields that have quantity 0.

I used the command:

foreach( $_POST as $nome_campo => $valor)
{ 
   $comando = "$" . $nome_campo . "='" . $valor . "';"; 
   eval($comando); 
}

However he brought all the inputs, I tried to treat not to show the ones that have qtd = 0 but the problem is in finding the variable I put a counter $i within foreach, then the variable name qtd I tried to call it that:

if ($qtd{$i} == 0 ) {}

But it didn’t work, as I do it fetching a dynamic variable?

$qtd1
$qtd2
$qtd3

Answer 1

First of all, answering what was asked, a path would be to use "variables":

foreach( $_POST as $nome_campo => $valor) { 
   $$nome_campo = $valor;
}

But this is far from a good idea. Any misuse of your PHP (for example, the client sending arbitrary data) will overwrite application variables.

As well remembered by Papa Charlie, PHP even has something ready that already does it automatically, the extract().

Like the above solutions (be the extract or the loop) has its inherent problems, a more elegant solution would be to use this structure:

<input type="hidden" name="nome_prod[]" value="Shampoo Hidratante Dazen Elegance">
<input data-theme="b" value="0" name="qtd[]" type="text" id="1"/>

And in PHP something like that:

$nome  = $_POST['nome_prod'];
$qtd   = $_POST['qtd'];

// aqui é só usar os dados como quiser, já estão indexados desde a captura.
$count = count( $qtd );
for( $i = 0; $i < $count; ++$i ) {
   echo 'Produto: '.$nome[$i].' - Quantidade: '.$qtd[$i]."<br>\n";
}

In a complete application, it is necessary to sanitize the data before use, obviously (regardless of the approach used).

As for not using zeroed values, just something like this inside the loop:

if( 0 + $qtd[$i] ) {
    // usa o valor como quiser
}

the code within the block of if will only be executed with values other than 0. The trick used is to force a cast with 0 + to treat the value as numerical (there are several ways to do this, this is one of them. see how to do the Casts and conversions in the PHP manual, in the variable part).