How to add new item to hash

Question

I\'m new to Ruby and don\'t know how to add new item to already existing hash. For example, first I construct hash:

hash = {item1: 1}

after

Answer 1

hash_items = {:item => 1}
puts hash_items 
#hash_items will give you {:item => 1}

hash_items.merge!({:item => 2})
puts hash_items 
#hash_items will give you {:item => 1, :item => 2}

hash_items.merge({:item => 2})
puts hash_items 
#hash_items will give you {:item => 1, :item => 2}, but the original variable will be the same old one.