How can I check if an index is defined?

Question

I have a loop that is getting data from a form:

foreach ($data as $d) {
    $id = $dataEntity->getId();
    $content = $data['form['.$id.']'];
    $dataEntity->setContent($content);
}

I have one problem. In the case that form['.$id.'] is valid than the code is working. But when it is not valid I get the error message:

Notice: Undefined index: form[5207c07b25]

So I tried to change the code like this

 foreach ($data as $d) {
     $id = $dataEntity->getId();
     $formData = "form['.$id.']";
     if(isset($formData)){
         $content = $formData;
     } else {
          $content = "";
     }
     $dataEntity->setContent($content);
 }

But still I get the same error message.

$formData = isset($data['form[' . $id . ']') ? $data['form[' . $id . ']' : ''; — Eakethet, Mar 22 '19 at 11:04
`isset` or `empty` or `(condition)?true : false` ternary or `$foo??$a??$b;` null coalescing — ArtisticPhoenix, Mar 22 '19 at 11:06
Why don't you check whether the combined index `$formData` exists in your `$data` array? The given code only checks whether the variable that you've defined a line earlier exists, which is, well, always true ;) — Nico Haase, Mar 22 '19 at 11:06
If you're running PHP7, `$formData = $data["form[$id]"] ?? '';` — Qirel, Mar 22 '19 at 11:08

score 1 · Accepted Answer · answered Mar 22 '19 at 11:07

1

You need to check if the index exists in the array. The index string itself will always be set:

 foreach ($data as $d) {
     $id = $dataEntity->getId();
     $formData = "form[".$id."]";
     if(isset($data[$formData])){
         $content = $data[$formData];
     } else {
          $content = "";
     }
     $dataEntity->setContent($content);
 }

answered Mar 22 '19 at 11:07

JensV

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2

just for kicks - for one action, I'd say it's better to go ternary: `$content = (isset($data[$formData]) ? $data[$formData] : '');` – treyBake Mar 22 '19 at 11:17
1

@treyBake If you use PHP 7 you should use `$content = $data[$formData] ?? ''` – JensV Mar 22 '19 at 12:13
Noice! Didn't know about this .. ! :D – treyBake Mar 22 '19 at 12:17

How can I check if an index is defined?

1 Answers1