rails get array of associated unique objects from array of objects

Question

Trip and Alert model are associate like: Trip has_many alerts

I have an object like @alerts = Alert.all

Now I want to find Array of unique Trip from @alerts

How can i do this ?

Gerry · Accepted Answer · 2017-05-16 15:16:43Z

2

You can use pluck method on @alerts, paired with uniq:

@alerts.pluck(:trip_id).uniq

The result will be an Array of unique Trip ids.

answered May 16, 2017 at 15:06

Gerry

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Comments

jvillian · Accepted Answer · 2017-05-16 15:05:53Z

1

You could try something like:

 Trip.where(id: @alerts.map(&:trip_id).uniq)

This:

  @alerts.map(&:trip_id).uniq

Gives you an array of unique trip ids based on your alerts.

BTW, this gives you an ActiveRecord::Relation, not an Array.

answered May 16, 2017 at 15:05

jvillian

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