Question

I have an array of hashes. Each entry looks like this:

- !map:Hashie::Mash 
  name: Connor H Peters
  id: "506253404"

I’m trying to create a second array, which contains just the id values.

["506253404"]

This is how I’m doing it

second_array = first_array.map { |hash| hash[:id] }

But I’m getting this error

TypeError in PagesController#home
can't convert Symbol into Integer

If I try

second_array = first_array.map { |hash| hash["id"] }

I get

TypeError in PagesController#home
can't convert String into Integer

What am I doing wrong? Thanks for reading.

Answer 1

You’re using Hashie, which isn’t the same as Hash from ruby core. Looking at the Hashie github repo, it seems that you can access hash keys as methods:

first_array.map { |hash| hash.id }

Try this out and see if that works–make sure that it doesn’t return the object_id. As such, you may want to double-check by doing first_array.map { |hash| hash.name } to see if you’re really accessing the right data.

Then, provided it’s correct, you can use a proc to get the id (but with a bit more brevity):

first_array.map(&:id)