Unable to fetch data from Laravel Eloquent Relationships

i wanted access the value of content_type_id .i tried like $courseChapters['chapter_content']['content_type_id'] , $courseChapters['content_type_id'] , $courseChapters[0]['content_type_id'] & $courseChapters['chapterContent']['content_type_id'].All these shows the error ErrorException: Undefined index: content_type_id . I also tried everything in the foreach loop i’ve commented below. Nothing works. Can someone tell me how to fix this?

/*foreach($courseChapters as $key){
   // $contentTypeId=$key->first(); //Call to a member function first() on int
  //  $contentTypeId=$key->first()->chapter_content; //Call to a member function first() on int
  //  $contentTypeId=$key['chapter_content']['content_type_id']; //error - Illegal string offset
  //  $contentTypeId=$key[0]['content_type_id']; ////error - Illegal string offset
  //  $contentTypeId=$key['content_type_id']; //error - Illegal string offset 'content_type_id' 
  }*/

$courseChapters = courseChapter::with(['chapterContent' => function ($q) use ($id) { $q->where('course_chapter_id', $id)->select('course_chapter_id','file_id','content_type_id');}])
            ->select('id','courseId', 'chapter_title', 'isExam', 'points')
            ->get()->toArray()[0];

Heading ## dd($courseChapters); shows array like given below:

array:6 [
  "id" => 4
  "courseId" => 24
  "chapter_title" => "chapter1"
  "isExam" => false
  "points" => 8
  "chapter_content" => array:1 [
    0 => array:3 [
      "course_chapter_id" => 4
      "file_id" => 1
      "content_type_id" => 1
    ]
  ]
]

Answer

Like this to access the first

echo $courseChapters['chapter_content'][0]['content_type_id'];

or like this to access all of them

foreach ($courseChapters['chapter_content'] as $chapter) {
    echo $chapter['content_type_id'];
}