Adding every nested resource's parameter to an array

Question

I want to add every nested resource's parameter to an array. The main resource is stream and the nested resources are videos

@stream = Stream.friendly.find(params[:id])
@firstvideo = @stream.videos.first

I want to store

array[] = [firstvideo.video_id , secondvideo.video_id , thirdvideo.video_id .....]

video_id is a parameter for each video. How can I create a method that will accomplish this?

Answer 1

Use pluck to get the video IDs from an association:

ids = Stream.friendly.find(params[:id]).videos.pluck(:id)

This will generate a select video_id from videos where ... query and only instantiate the array of returned IDs, side-stepping the expensive process of building Video objects for each record.

If you have an already instantiated list of Video objects, use map to produce an array of IDs:

ids = @videos.map(&:id) # equivalent to .map { |v| v.id }