Remove an item from each hash in an Array of hashes

Question

I have an array of hashes like this:

array = [{ "id"=>"ABC", "account"=>"XYZ", "date"=>"2014-07-21", "amount"=>200, "score"=>{"location"=>{"city"=>1, "state"=>1}, "name"=>1}, "cat"=>#<Tipper::Category:0xb666fb0 @type={"primary"=>"special"}, @hierarchy=["Transfer","Withdrawal", "ATM"], @id="21012002" >, "state"=>"CA" }, {"id=>"XYZ","account"=>"987"}]

I want to iterate through each hash in the array and remove the "category" piece from each hash and produce an array of hashes without the "category" item in any of the hashes. I tried this:

filtered_array = array.reject { |t| array.include? t['cat'] }

This is not doing it.

The data is called array, but the code snippet never references array — Wayne Conrad
– Wayne Conrad, Commented Jun 6, 2015 at 9:36

Nafaa Boutefer · Accepted Answer · 2015-06-05 21:53:35Z

You can use map and delete

this will work the actual instances of the hashes, so the array will be modified.

array.each{ |hash| hash.delete('cat') }

you can do this to get a new array and keep the first one non touched.

new_array = array.map do |hash| new_hash = hash.dup new_hash.delete('cat') new_hash }

Zoran · Accepted Answer · 2015-06-05 22:26:39Z

Assuming you have an array of hashes:

array = [ {"id" => 1, "name" => "bob", "cat" => "dog"}, {"id" => 2, "name" => "jim", "cat" => "mouse"}, {"id" => 1, "name" => "nick", "cat" => "fish"} ]

You can do something like the following:

array.map { |hash| hash.reject {|k, v| k == "cat" } }

This returns a new array of hashes with the cat pairs removed, while still preserving the original array:

=> [{:id=>1, :name=>"bob"}, {:id=>2, :name=>"jim"}, {:id=>1, :name=>"nick"}]

Hope it helps!

You have to return the hash in the map block, because delete will return the value of the deleted key. So your solution will return an array of the categories.
And you should note that the hashes in the array will all be modified, so the subject array and the resulting array are identical, and contains the same instances. Which is not what I would suggest.
Thanks for your feedback! I have actually just modified my code to use reject. This returns the desired array of hashes, while still preserving the original array.

Collectives™ on Stack Overflow

Remove an item from each hash in an Array of hashes

2 Answers 2

Comments

3 Comments

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

3 Comments

Related