loop through unknown number of POST elements, keeping groups together

schwim

Hi there everyone!

I've got a form that can have any number of results in it, so the form looks like so, if there are 5 results:

	<input type="text" size="15" name="ciw_name-1" placeholder="Name"> <input type="text" size="25" name="ciw_url-1" placeholder="URL"> $<input type="text" size="5" name="ciw_price-1" placeholder="Price"><br>

<input type="text" size="15" name="ciw_name-2" placeholder="Name"> <input type="text" size="25" name="ciw_url-2" placeholder="URL"> $<input type="text" size="5" name="ciw_price-2" placeholder="Price"><br>

<input type="text" size="15" name="ciw_name-3" placeholder="Name"> <input type="text" size="25" name="ciw_url-3" placeholder="URL"> $<input type="text" size="5" name="ciw_price-3" placeholder="Price"><br>

<input type="text" size="15" name="ciw_name-4" placeholder="Name"> <input type="text" size="25" name="ciw_url-4" placeholder="URL"> $<input type="text" size="5" name="ciw_price-4" placeholder="Price"><br>

<input type="text" size="15" name="ciw_name-5" placeholder="Name"> <input type="text" size="25" name="ciw_url-5" placeholder="URL"> $<input type="text" size="5" name="ciw_price-5" placeholder="Price"><br>

There could be 1 or 20 of these. Each one has three elements that need to remain grouped together for db insertion. "ciw-name-'x', ciw-url-'x' and ciw-price-'x' will get inserted into a db row together, keeping the numerical value of x together.

I am having problems figuring out how to both loop through the unknown number of groupings, as well as figuring out how to capture the values for a form element who's name is dynamic, due to the changing number at the end of each name.

Could someone help me figure out how to do such a thing?

Thanks for your time!

laserlight

You know the format of the names, and you know there are 1 (to?) 20 of these, but presumably you need to count them to know how many there really are. Is the range of numbers guaranteed to be contiguous starting from 1, i.e., if there are 5 of them, the numbers are guaranteed to be 1, 2, 3, 4, and 5, not say, 1, 3, 6, 10, and 12? If so, it sounds quite simple: you just run a loop with a counter from 1 to 20, then check that ciw_name-1 is a valid key for $POST, then ciw_name-2, ciw_name-3, etc, e.g., using sprintf to format the key with the counter. When you discover that the current key does not exist in $POST, you know you have reached the end of the list.

pbismad

You would use an array for the name attributes and if the 1,2,3... values are significant to the meaning of the data (probably not if entering/inserting new data), you would use them as the array index value, otherwise you would leave the array index empty and let it be auto-numbered.

User either - name="ciw_name[]" (auto numbered index values) or name="ciw_name[1]" (specifically number the array index yourself when you dynamically produce the form.) Repeat for the other form fields.

In either case, this will result in a php array variable - $_POST['ciw_name'] that you can operate on using php array functions, such as a foreach(){} loop.

Derokorian

I would probably just use array notation:

	<input type="text" size="15" name="ciw_name[]" placeholder="Name"> <input type="text" size="25" name="ciw_url[]" placeholder="URL"> $<input type="text" size="5" name="ciw_price[]" placeholder="Price"><br>

Then you could just loop through one array, using the key for the others:

if (!empty($_POST)) {
   foreach ($_POST['ciw_name'] as $key => $name) {
      $url = $_POST['ciw_url'][$key];
      $price = $_POST['ciw_price'][$key];

  // Don't do this, use prepared statements and such
  $db->query("INSERT INTO ciw (index, name, url, price) values ($key, '$name', '$url', '$price')");
   }
}

Edit: pbismad beat me, but we're talking about doing the same thing.

schwim

Hi there and thanks for everyone's help!

I've attempted to write an array loop and it seems to loop correctly, but I'm having a problems assigning the dynamic values. Here's my loop:

if(ISSET($_POST['mod_wholesalers'])){
	$ciwsub_num = 1;
	//print_r($_POST);
	foreach($_POST as $key => $value) {
		if (strpos($key, 'ciw_name') === 0) {
			echo $ciwsub_num;
			$sub_ciw_name = ${'ciw_name-'.$ciwsub_num};
			$sub_ciw_url = ${'ciw_url-'.$ciwsub_num};
			$sub_ciw_price = ${'ciw_name-'.$ciwsub_num};

		echo"
		Name: ".$sub_ciw_name."<br>
		URL: ".$sub_ciw_url."<br>
		Price: ".$sub_ciw_price."<br>
		";

		$ciwsub_num = ++$ciwsub_num;
	}
}
}

$sub_ciw_name, url and price are showing as undefined, so I think I've messed up here somehow:

			$sub_ciw_name = ${'ciw_name-'.$ciwsub_num};
			$sub_ciw_url = ${'ciw_url-'.$ciwsub_num};
			$sub_ciw_price = ${'ciw_name-'.$ciwsub_num};

Is there another way i should be handling this?

laserlight

Yeah, using arrays would be better. My suggestion was with the assumption that you have no control over the format of the form element names.

However, if you are going to use arrays, then I suggest that you group them instead of having parallel arrays, e.g.,

<input type="text" size="15" name="ciw[1][name]" placeholder="Name"> <input type="text" size="25" name="ciw[1][url]" placeholder="URL"> $<input type="text" size="5" name="ciw[1][price]" placeholder="Price"><br>

<input type="text" size="15" name="ciw[2][name]" placeholder="Name"> <input type="text" size="25" name="ciw[2][url]" placeholder="URL"> $<input type="text" size="5" name="ciw[2][price]" placeholder="Price"><br>

<input type="text" size="15" name="ciw[3][name]" placeholder="Name"> <input type="text" size="25" name="ciw[3][url]" placeholder="URL"> $<input type="text" size="5" name="ciw[3][price]" placeholder="Price"><br>

<input type="text" size="15" name="ciw[4][name]" placeholder="Name"> <input type="text" size="25" name="ciw[4][url]" placeholder="URL"> $<input type="text" size="5" name="ciw[4][price]" placeholder="Price"><br>

<input type="text" size="15" name="ciw[5][name]" placeholder="Name"> <input type="text" size="25" name="ciw[5][url]" placeholder="URL"> $<input type="text" size="5" name="ciw[5][price]" placeholder="Price"><br>

This way, you have a single array with the data, i.e., $POST['ciw']. That said, note that even with this, you cannot assume that just because $POST['ciw'][1]['name'] is not empty that $_POST['ciw'][1]['price'] exists: you should still check with isset or empty or check the key against the array, and validate your incoming data.

EDIT:

schwim wrote:
$sub_ciw_name, url and price are showing as undefined, so I think I've messed up here somehow:

Yes, you have. You should be accessing $POST['ciw_name-1'], etc. Therefore:

for ($i = 1; $i <= 20; $i++) {
    $ciw_name = sprintf('ciw_name-%d', $i);
    $ciw_url = sprintf('ciw_url-%d', $i);
    $ciw_price = sprintf('ciw_price-%d', $i);
    if (isset($_POST[$ciw_name], $_POST[$ciw_url], $_POST[$ciw_price])) {
        // ...
    } else {
        break; // ?
    }
}

schwim

With the form converted as instructed, is this an acceptable method of looping through the arrays?

if(ISSET($_POST['ciw'])){
	foreach($_POST['ciw'] as $ciw) {
		foreach($ciw as $key => $value) {
			if($key == 'name'){
				$sub_ciw_name = $value;
			}elseif($key == 'url'){
				$sub_ciw_url = $value;
			}elseif($key == 'price'){
				$sub_ciw_price = $value;
			}
		}

echo "name: ".$sub_ciw_name."<br>
url: ".$sub_ciw_url."<br>
price: ".$sub_ciw_price."<br>";

}
}

I know I need to validate and more, but I'm wondering if anything else should be done with the loops themselves to make it nicer.

laserlight

That is rather convoluted when you could have just written:

if (isset($_POST['ciw']) && is_array($_POST['ciw'])) {
    foreach ($_POST['ciw'] as $ciw) {
        if (isset($ciw['name'], $ciw['url'], $ciw['price'])) {
            echo "name: " . $ciw['name'] . "<br>
            url: " . $ciw['url'] . "<br>
            price: " . $ciw['price'] . "<br>";
        }
    }
}