Parse the first level keys of $_POST, then use the numeric suffix while looping

Question

I have a form that contains a number of fields with names item1, item2, item13, item43 etc, each time those fields are different because they are populated in the form with AJAX.

When user submits I need to perform the following:

foreach ($_POST['itemX']['tagsX'] as $tag) {
    inserttag($tag, X);
}

where X = 1,2,13,43 etc. How can I iterate the $_POST values and perform the above only for the values of those that their name begins with 'item' followed by an the X identifier?

The posted data has the following format:

$_POST = [
    'item38' => ['tags38' => ['aaa', 'bbb']],
    'item40' => ['tags40' => ['ccc', 'ddd']],
    'item1' => ['tags1' => ['eee', 'zzz']],
];

Binate

Answer 1

foreach($_POST as $key => $value)
{
    if (strstr($key, 'item'))
    {
        $x = str_replace('item','',$key);
        inserttag($value, $x);
    }
}

Gambado

The PHP documentation has an explicit note that says not to use strstr() to check the existence of a substring for performance reasons. – Kalikalian

Answer 2

You can loop through $_POST with foreach like this:

foreach ($_POST as $key => $value) { ... }

And within the loop you can evaluate whether each key found by the loop matches your criteria. Something like this:

foreach ($_POST as $key => $value){
   if (substr($key, 0, 4) == "item") {
      $identifier = substr($key, 4);
      if (isset($value['tag' . $identifier])) { inserttag('tag', $identifier); }
   }
}

I'm not 100% sure what is actually real and what is just a placeholder in your question though. Maybe I took something for solid fact that actually isn't. You might need to explain your wishes in more detail. ;)

Mohammedmohammedan

Answer 3

Try:

foreach($_POST as $key=>$value){
    inserttag($key, $value);
}

$key will be the name of the element and $value will be the value.

Allpurpose

Answer 4

Loop through $_POST and see if the key contains 'item'.

foreach($_POST as $key=>$value){
    if(preg_match('/item(\d*)/', $key, $match) === 1){
        inserttag($value, $match[1]);
    }
}

Atlantis

Wouldn't you have to iterate through $value looking for keys that match tagsX then pass those values to inserttag – Moralez

I was just thinking this @Musa! – Coronado

@Musa: Reading the question again, yeah, sounds like I would. I'll leave that as a challenge for the OP ^^ – Atlantis

Please check my question, I've updated it with the solution. Thanks everyone for your time and effort. – Binate

Answer 5

Use sscanf() to validate and extract the identifying integer with one function call.

Code: (Demo)

foreach ($_POST as $itemId => $set) {
    if (sscanf($itemId, 'item%d', $id)) {
        foreach ($set["tags$id"] as $v) {
            inserttag($v, $id);
        }
    }
}

Kalikalian

Answer 6

If your item numbers are sequential, it's possible to use FOR to this intent. Concatenate the number ($i) with the item name on the index, like that:

for ($i=0; $i <= $numbeOfItems; $i++) {
 inserttag($_POST['item' . $i]['tags' . $i]), $i;
}

Gauthier

The asked question does not indicate that the input array is indexed. – Kalikalian