How to turn multiple variables into one PHP

Question

I have a form with 8 input fields that take the entered value, I pick them by the POST but only 1 of the 8 fields is filled by the user, and in the POST I’m passing the 8 values even having only 1 filled, have as I turn the 8 variable of the post in one?

In case I’m doing it

$nbuffet1 = $_POST['qtdbuffet1'];
$nbuffet2 = $_POST['qtdbuffet2'];
$nbuffet3 = $_POST['qtdbuffet3'];
$nbuffet4 = $_POST['qtdbuffet4'];
$nbuffet5 = $_POST['qtdbuffet5'];
$nbuffet6 = $_POST['qtdbuffet6'];
$nbuffet7 = $_POST['qtdbuffet7'];
$nbuffet8 = $_POST['qtdbuffet8'];

$corpoMSG = " 

<strong>Quantidade Buffet:</strong> $nbuffet1 $nbuffet2 $nbuffet3 $nbuffet4 $nbuffet5 $nbuffet6 $nbuffet7 $nbuffet8<br>

 ";

Answer 1

With PHP you can check which value is filled and use it. Like the other values will be strings empty, just make a logical operation between them:

$quantidade = $_POST['qtdbuffet1'] 
            || $_POST['qtdbuffet2'] 
            || ... 
            || $_POST['qtdbuffet8'];

Thus, regardless of which value has been filled in, it will be attributed to $quantidade. Can do:

$corpoMSG = "<strong>Quantidade Buffet:</strong> {$quantidade}<br>";

But there is no point in owning 8 fields to send only 1 value. See below how you can work around this using Javascript.

---

This is what we call the XY problem. You have an interface problem, in HTML, but you want to solve it in PHP. You can, but it’s going to be funny.

As you put it, you have 8 choice options on the screen for the user and as the choice will be limited the amount values. You have set 8 different fields, configuring as needed and it seems that you only display one as per user selection. As a consequence you will have 8 values in PHP and only one has been filled. By the HTTP message you only want to send one value: quantity. It doesn’t matter where it came from. Having 8 fields to send 1 value doesn’t make any sense.

If you need different validation rules according to the selected option, use Javascript:

const loja = document.querySelector('#lojaInput');
const quantidade = document.querySelector('#quantidadeInput');

loja.addEventListener('change', function () {
  quantidade.max = loja.options[loja.selectedIndex].dataset.max;
});

input:invalid {
  background-color: pink;
  border: 2px solid red;
}

<form>
  <select name="loja" id="lojaInput">
    <option value="1" data-max="10">Loja 1</option>
    <option value="2" data-max="20">Loja 2</option>
    <option value="3" data-max="30">Loja 3</option>
  </select>

  <label>
    Quantidade:
    <input id="quantidadeInput" type="number" name="quantidade" max="10" value="0">
  </label>

  <button type="submit">Enviar</button>
</form>

Realize the value of max country quantidade is defined by the property data-max of select. If selected store 1 the maximum will be 10; store 2 will be 20 and store 3 will be 30.

In PHP, just take the value $_POST['quantidade']. To validate the value also in backend, use the value of $_POST['loja'] as a reference.

Answer 2

You can concatenate with the operator . .

    $resultado = $nbuffet1 . ' ' . $nbuffet2 . ' ' . $nbuffet3 . ' ' . $nbuffet4 . ' ' . $nbuffet5 . ' ' . $nbuffet6 . ' ' . $nbuffet7 . ' ' . $nbuffet8;
$corpoMSG = " 

<strong>Quantidade Buffet:</strong> $resultado <br>

 ";

or use Heredocs:

$corpoMSG = <<<EOD
<strong>Quantidade Buffet:</strong>$nbuffet1 $nbuffet2 $nbuffet3 $nbuffet4 $nbuffet5 $nbuffet6 $nbuffet7 $nbuffet8<br>
EOD;