Laravel 5.2 - use attach method with array values - php

Question

I am creating a blog with posts in Laravel 5.2. Every post is going to have multiple tags. I created a relationship between posts and tags. When the post is created, I am trying to attach multiple tags to it.
Controller function
public function store(Request $request)
{
$attributes = [
'author_id' => Auth::user()->id,
'title' => $request->input('title'),
'text' => $request->input('text'),
];
$post = Post::create($attributes);
// Get the tag ids from the the tags table in the database
$tagsList = $request->input('tags');
$tags = explode(",", $tagsList);
$tagIds = array();
foreach($tags as $tag) {
$tagIds[] = Tag::select('id')->where('name', $tag)->limit('5')->get();
}
dd($tagIds); // Output below
$post->tags()->attach($tagIds); // not working
}
dd($tagIds) output
array:2 [▼
0 => Collection {#316 ▼
#items: array:1 [▼
0 => Tag {#317 ▼
#fillable: array:2 [▶]
#connection: null
#table: null
#primaryKey: "id"
#keyType: "int"
#perPage: 15
+incrementing: true
+timestamps: true
#attributes: array:1 [▼
"id" => 32
]
#original: array:1 [▶]
#relations: []
#hidden: []
#visible: []
#appends: []
#guarded: array:1 [▶]
#dates: []
#dateFormat: null
#casts: []
#touches: []
#observables: []
#with: []
#morphClass: null
+exists: true
+wasRecentlyCreated: false
}
]
}
1 => Collection {#318 ▼
#items: array:1 [▼
0 => Tag {#319 ▼
#fillable: array:2 [▶]
#connection: null
#table: null
#primaryKey: "id"
#keyType: "int"
#perPage: 15
+incrementing: true
+timestamps: true
#attributes: array:1 [▼
"id" => 36
]
#original: array:1 [▶]
#relations: []
#hidden: []
#visible: []
#appends: []
#guarded: array:1 [▶]
#dates: []
#dateFormat: null
#casts: []
#touches: []
#observables: []
#with: []
#morphClass: null
+exists: true
+wasRecentlyCreated: false
}
]
}
]
The returned array contains correct ids of the tags. I just do not know how to get them into a format, so that they can be passed to the attach method.
I would be very thankful for any kind of help!

Answer 1

For convenience, attach and detach also accept arrays of IDs as input:
$tagIds = array();
foreach($tags as $tag) {
$tagIds[] = Tag::select('id')->where('name', $tag)->first()->id;
}
dd($tagIds); // Output below
/*
Array
(
[0] => 1
[1] => 3
[2] => 5
)
*/
$post->tags()->attach($tagIds);

Answer 2

You can just use pluck to get the array of ids from collection, no need to loop to get the ids of tags.
example:
$tags = Tag::pluck('id');
$post->tags()->attach($tags);
Please also refer to the documentation
https://laravel.com/docs/9.x/collections#method-pluck