Rails filtering array of objects by attribute value

Try :

This is fine :

@logos = @attachments.select { |attachment| attachment.file_type == 'logo' }
@images = @attachments.select { |attachment| attachment.file_type == 'image' }

but for performance wise you don't need to iterate @attachments twice :

@logos , @images = [], []
@attachments.each do |attachment|
  @logos << attachment if attachment.file_type == 'logo'
  @images << attachment if attachment.file_type == 'image'
end

If your attachments are

@attachments = Job.find(1).attachments

This will be array of attachment objects

Use select method to filter based on file_type.

@logos = @attachments.select { |attachment| attachment.file_type == 'logo' }
@images = @attachments.select { |attachment| attachment.file_type == 'image' }

This will not trigger any db query.