PHP foreach doesn't select the dropdown list - php

Question

I have a this html:
<option value="yes">Yes</option>
<option value="no">No</option>
and my php:
<?php
exec('uci get sms_gateway.setting.filter',$filt);
echo '<form action='.$_SERVER['PHP_SELF'].' method="post">
<select name="filter">';
foreach ($filt as $value){
if ($filt = "yes"){
echo '<option value="'.$value.'" selected>Yes</option><br>
<option value="no">No</option><br>ini yes';}
else {
echo '<option value="yes">Yes</option><br>
<option value="'.$value.'" selected>No</option><br> ini no';
}
}
echo '
</select>
<input type="submit" name="submit" value="Submit">';
if(isset($_POST['submit'])){
{
$data = $_POST['filter'];
echo "<br>halo ". $data;
}
}
?>
the $filt only has one string it's either yes or no
when it's yes I want the yes part on the dropdown menu selected, but when it's no I want the no part on the dropdown selected. How should I do that?

Answer 1

This bit of code:
foreach ($filt as $value) you're doing as $value so use:
foreach ($filt as $value){
if ($value == "yes"){
Then you have 2 sets of braces which are not needed; they're just extra keystrokes for nothing:
if(isset($_POST['submit'])){
{
$data = $_POST['filter'];
echo "<br>halo ". $data;
}
}
Change it to:
if(isset($_POST['submit'])){
$data = $_POST['filter'];
echo "<br>halo ". $data;
}
Another thing I spotted, a missing closing </form> tag.
Just for the record, you were also assigning using a single = sign, instead of comparing using two == for:
if ($filt = "yes")
which theoretically should have read as
if ($filt == "yes")
Add error reporting to the top of your file(s) which will help find errors.
<?php
error_reporting(E_ALL);
ini_set('display_errors', 1);
// rest of your code
Sidenote: Error reporting should only be done in staging, and never production.

Answer 2

There's many things wrong with your code, you're treating "$filt" as both an array and a value, you're also assigning (=) instead of comparing. I'll give you a working example instead of trying to fix your code:
<?php $possibleValues = array('yes', 'no'); // All possible options ?>
<?php $valueYouWantSelected = 'yes'; // 'yes' will be selected ?>
<select>
<?php foreach ($possibleValues as $value): ?>
<?php $selected = ($valueYouWantSelected == $value) ? 'selected' : null; // Select this option if it equals $valueYouWantSelected ?>
<option value="<?php echo $value;?>" <?php echo $selected; ?>>
<?php echo $value; ?>
</option>
<?php endforeach ?>
</select>
If you're confused about how I assign $selected, check out ternary operators.
Also, I'm using alternative syntax, it makes it easier to organize PHP code within HTML (and colors code properly in your editor).