how to set selected multiple combo box based on array - php

Question

I have two sets of array ,first array contains all categories called "all", and second array contains selected categories called "selected", I want to populate this concept to multiple combo box,
$all = [
0 => [
'id'=>1,
'name' => 'news'
],
1 => [
'id'=>2,
'name' => 'tips'
],
2 => [
'id'=>3,
'name' => 'trick'
],
3 => [
'id'=>4,
'name' => 'review'
]
];
$selected = [
0 => [
'id'=>2,
'name' => 'trick'
],
1 => [
'id'=>4,
'name' => 'review'
],
];
I've try to do foreach in foreach , but i have duplicated data when show in combo box, i want to have all data from "all" shown with selected data from "selected".
i just solved my problem in deferent way , first i add default pair of key and value "sel"=>0 in "all" array set, then i loop trough array "all" and array "sel" to get similar value and when it match change sel key to 1 ,this code for further explanation
public static function compare($sel,$all){
// add sel key with default value = 0
foreach($all as $k=>$v){
$all[$k]['sel'] = 0;
}
foreach($all as $k=>$v){
foreach($sel as $k2=>$v2){
// when match change sel to 1
if($v['id'] == $v2['id']){
$all[$k]['sel'] = 1;
}
}
}
return $all;
}
final result :
$all = [
0 => [
'id'=>1,
'name' => 'news',
'sel' => 0
],
1 => [
'id'=>2,
'name' => 'tips',
'sel' => 0
],
2 => [
'id'=>3,
'name' => 'trick',
'sel' => 1
],
3 => [
'id'=>4,
'name' => 'review',
'sel' => 1
]
];
just add if condition when $all['sel'] = 1 they should be selected, thanks all :D

Answer 1

You can get the intersection of both arrays with array_uintersect and a custom callback function (compare).
function compare($a, $b){
if($a['id'] == $b['id']){
return 0;
}
return 1;
}
$res = array_uintersect($selected, $all,"compare");
print_r($res);
>Array ( [0] => Array ( [id] => 2 [name] => trick ) [1] => Array ( [id] => 4 [name] => review ) )
After that you only need to loop through the final array and set the corresponding check boxes.
If you want to compare by name just create another callback function.
function compare2($a, $b){
if($a['name'] == $b['name']){
return 0;
}
return 1;
}

Answer 2

The duplicates are caused by the inner for loop continuing to create select elements even after it has found a selected element. You can avoid having an inner loop and using php's in_array() function to check if $all is in $selected like this:
$x = '';
foreach($all as $a){
if(in_array($a, $selected)){
$x .= '<option selected>'.$a['id'].'Selected </option>';
}else{
$x .= '<option>'.$a['id'].'Not selected </option>';
}
}
echo $x;
Note that in_array will check all values of the elements, so for example element with id 2 but different name will appear as not selected. You may want to change both names to tips. I hope that helps.