Loop over one array and check if element exist in another array - php

Question

I have two arrays, the first one is
$practice_areas = array(
array(
"id" => 1,
"name" => "Administrative",
"form_id" => 1
),
array(
"id" => 2,
"name" => "Admiralty & Maritime",
"form_id" => 1
),
array(
"id" => 3,
"name" => "Agricultural",
"form_id" => 1
),
array(
"id" => 4,
"name" => "Alternative Dispute Resulution",
"form_id" => 1
),
array(
"id" => 5,
"name" => "Antitrust & Trade Regulation",
"form_id" => 1
),
array(
"id" => 6,
"name" => "Appellate Practice",
"form_id" => 1
)
);
and the second one is $selected_id
$selected_id = array(
array(
"id" => 1,
"lawyer_id" => 2,
"practice_area_id" => 3
),
array(
"id" => 2,
"lawyer_id" => 2,
"practice_area_id" => 4
)
);
And this is my current code:
<label>Practice area(s) *</label>
<select id="practice_areas" multiple="multiple" name="practice_areas[]">
<option value="" selected="selected"></option>
<?php foreach($practice_areas as $practice_area) {?>
<option value="<?php $practice_area['id'] ?>" <?php ($selected_id->practice_area_id == $practice_area['id']) ? 'selected="selected"' : ''; ?>><?php $practice_area['name'] ?></option>
<?php } ?>
</select>
I want to select all the options that exist in the $selected_id array. I'm having a bad time on writing this loop correctly.
EDIT1
when I try to use the
foreach ($selected_id as $sel) {
$is_selected[$sel["practice_area_id"]] = true;
}
I've got this result.
$selected_id = array(
array(
"id" => 1,
"lawyer_id" => 2,
"practice_area_id" => 3
),
array(
"id" => 2,
"lawyer_id" => 2,
"practice_area_id" => 4
),
true,
true
);

Answer 1

You could do it like this:
<label>Practice area(s) *</label>
<select id="practice_areas" multiple name="practice_areas[]">
<option value="" selected></option>
<?php
// First create an array that is keyed by practice_area_id for selected items
foreach ($selected_id as $sel) {
$is_selected[$sel["practice_area_id"]] = true;
}
foreach($practice_areas as $practice_area) {
?>
<option value="<?= $practice_area['id'] ?>"<?=
(isset($is_selected[$practice_area['id']]) ? ' selected>' : '>') .
$practice_area['name'] ?></option>
</option>
<?php } ?>
</select>
Note that you had several <?php tags that did not echo anything inside the option tags. You can use instead the <?= tag for that.
Also the selected attribute in an option does not require a value. Just its presence is enough. The same goes for the multiple attribute of the select tag.
Finally, the -> operator only works on objects, but you have arrays, so you should use the bracket notation throughout.
See the above code run on eval.in