Hash.except() doesn't work with symbol keys

Question

I have a piece of code where this line:

user.attributes.except('created_at', 'created_by', 'updated_at', 'updated_by', 'id')

works (returns the hash with the keys passed as arguments removed from it), whereas changing it to:

user.attributes.except(:created_at, :created_by, :updated_at, :updated_by, :id)

doesn't (the returned hash still contains all the keys). How is this possible?

Answer 1

Because attributes returns a Hash with keys as string and not symbol.

http://apidock.com/rails/ActiveRecord/Base/attributes

and as said by others, String != Symbol.

puts :a == 'a'
# => false

Answer 2

This happens because the keys in user.attributes are strings. You can symbolize them using symbolize_keys method and then use except with symbols like this.

user.attributes.symbolize_keys.except(:created_at, :created_by, :updated_at, :updated_by, :id)