In Ruby, a hash is a collection of key-value pairs. You can create a hash using the curly braces {} or the Hash.new method.
Here's an example of creating a hash with curly braces:
my_hash = { "name" => "John", "age" => 30, "city" => "New York" }
In this example, we've created a hash with three key-value pairs. The keys are "name", "age", and "city", and the values are "John", 30, and "New York", respectively.
You can also create a hash using the Hash.new method:
my_hash = Hash.new
my_hash["name"] = "John"
my_hash["age"] = 30
my_hash["city"] = "New York"
In this example, we've initialized an empty hash using the Hash.new method. Then, we've added key-value pairs using the hash's indexing operator [].
Once you've created a hash, you can access its values using the keys:
puts my_hash["name"] # Output: John
puts my_hash["age"] # Output: 30
puts my_hash["city"] # Output: New York
You can also iterate over a hash using the each method:
my_hash.each do |key, value|
puts "#{key}: #{value}"
end
This will output:
name: John
age: 30
city: New York