I have this loop:

```
  stations = Station.where(...)
  stations.all.each do |s|
    if s.city_id == city.id
      show_stations << s
    end
  end

```

This works well, but because of looping the all the data, I think it's kinda slow. I've tried to rewrite it with using `select`, like this:

```
show_stations << stations.select { |station| station.city_id == city.id}

```

But the amount of saved data into `show_stations` is different compared to the `each` version and then, the data are in different format (array/object).

Is there any better/faster way to rewrite the loop version?