PHP form error - Warning: Invalid argument supplied for foreach()

Question

I am a beginner to PHP, currently working on a long survey. Below is the code which is causing issues, the data from the checked boxes are added to a database:

$_q4 = (isset($_GET['check_q4']) ? $_GET['check_q4'] : null);
$q4 = '';
foreach($_q4 as $a4) {
$q4 .= $a4;}


<div class="group v-group">
<label><input type="checkbox" name="check_q4[]" value="1"> Checkbox 1</label>
<label><input type="checkbox" name="check_q4[]" value="2"> Checkbox 2</label>
<label><input type="checkbox" name="check_q4[]" value="3"> Checkbox 3</label>
</div>

Error:

Warning: Invalid argument supplied for foreach() in C:\inetpub\wwwroot\submit_form.php on line 79 Failed to run query: SQLSTATE[22001]:

Many thanks for you help.

possible duplicate of Invalid argument supplied for foreach() — Narendrasingh Sisodia
– Narendrasingh Sisodia, Commented May 12, 2015 at 8:59
Can you echo out the contents of your $_q4 variable? It sounds like the $_GET variable is empty, so null is being assigned to the variable. Are you actually posting the form via "GET", or are you posting via the "POST" method? — VerySeriousSoftwareEndeavours
– VerySeriousSoftwareEndeavours, Commented May 12, 2015 at 9:00

Masiorama · Accepted Answer · 2015-05-12 08:59:14Z

3

Since $_q4 can be null, you should check if it is the case, because you cannot traverse an empty/null variable with foreach.

Try with something like this:

if(!empty($_q4)){
  foreach($_q4 as $a4) {
   $q4 .= $a4;
  }
}

answered May 12, 2015 at 8:59

Masiorama

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Comments

kamal pal · Accepted Answer · 2015-05-12 09:05:30Z

0

Please make sure that your Form's request method is get

$_q4 = (isset($_GET['check_q4']) ? $_GET['check_q4'] : null);
$q4 = '';
if(is_array($_q4)){
  foreach($_q4 as $a4) {
  $q4 .= $a4;}
}

answered May 12, 2015 at 9:05

kamal pal

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