getting emptied while checking if an array value exists

I wanted to insert the id values of $courseCat if that id is not present in $m.In the below code, i feel the $m array is getting emptied every time and so, all id's are getting inserted to the $m ,as the result of dump($m) indicates.How can i fix this?

$m=[];
$courseCat = MyCourse::where('course_id', $key['courseId'])->get()->toArray();
foreach($courseCat as $k=>$c){
  // dump($courseCat);
    if(!in_array($c['id'],$m)){
           array_push($m,$c['id']);
      }
}
//dump($m);

dump($courseCat); shows the following result

    array:2 [
      0 => array:19 [
        "id" => 2
        "course_id" => 18
      ]
      1 => array:19 [
        "id" => 3
        "course_id" => 18
      ]                                   
    ]
   array:2 [
      0 => array:19 [
        "id" => 2
        "course_id" => 18
      ]
      1 => array:19 [
        "id" => 3
        "course_id" => 18
      ]                                   
    ]
    array:2 [
      0 => array:19 [
        "id" => 5
        "course_id" => 1
      ]                                
      1 => array:19 [
        "id" => 6
        "course_id" => 1
      ]
    ]
    array:2 [
      0 => array:19 [
        "id" => 5
        "course_id" => 1
      ]                                 
      1 => array:19 [
        "id" => 6
        "course_id" => 1
      ]
    ]

dump($m) shows the below result:

array:2 [
  0 => 2
  1 => 3
]
array:2 [
  0 => 2
  1 => 3
]
array:2 [
  0 => 6
  1 => 5
]
array:2 [
  0 => 6
  1 => 5
]

Below attached images are the result of the query MyCourse::where('course_id', $key['courseId'])->get().

[enter image description here]1

[enter image description here]2

[enter image description here]3

Expected result :

dump($m) should show the below result

[0=>2,
1=>3,
2=>5,
3=>6]

CodePudding user response：

I think it's because you have an outer loop not shown in the question. You need to declare $m before the outer loop:

$m=[];

foreach($keys as $key){
    
    $courseCat = MyCourse::where('course_id', $key['courseId'])->get()->toArray();
    foreach($courseCat as $k=>$c){
      
        if(!in_array($c['id'],$m)){
               array_push($m,$c['id']);
          }
    }
    
}
dump($m);

CodePudding user response：

If you want all the values of a column from your query you can use pluck:

MyCourse::where('course_id', $key['courseId'])->pluck('id')

Now you have a list of all the 'id's.

Laravel 8.x Docs - Database - Running Database Queries - Retrieving a List of Column Values pluck