How to remove a key from Hash and get the remaining hash in Ruby/Rails?

Question

To add a new pair to Hash I do:

{:a => 1, :b => 2}.merge!({:c => 3})   #=> {:a => 1, :b => 2, :c => 3}

Is there a simi

Answer 1

You can use except! from the facets gem:

>> require 'facets' # or require 'facets/hash/except'
=> true
>> {:a => 1, :b => 2}.except(:a)
=> {:b=>2}

The original hash does not change.

EDIT: as Russel says, facets has some hidden issues and is not completely API-compatible with ActiveSupport. On the other side ActiveSupport is not as complete as facets. In the end, I'd use AS and let the edge cases in your code.

Answer 2

Why not just use:

hash.delete(key)

Answer 3

in pure Ruby:

{:a => 1, :b => 2}.tap{|x| x.delete(:a)}   # => {:b=>2}