In Ruby, it is possible to decompose the elements of arrays/hashes into distinct variables. Since values appear within arrays in a index order, they are unpacked into variables in the same order.
# Decompose of an array
>> fruits = ["apple", "banana", "cherry"]
>> x, y, z = fruits
>> x
=> "apple"
In this case we are going to use decompose for a method call, (with arrays only one splat needed *).
def send_welcome_email(name, email, signup_date)
puts "Sending welcome email to: #{name}"
puts "Email: #{email}"
puts "Signed up on: #{signup_date}"
end
# Array of user information
user_data = ['Jane Doe', 'jane.doe@example.com', '2023-04-01']
# Using splat to pass an array of elements
send_welcome_email(*user_data) 👈
# This code will output:
Sending welcome email to: Jane Doe
Email: jane.doe@example.com
Signed up on: 2023-04-01
Now we are going to decompose for a hash, (two splats needed **).
def configure_user(profile:, preferences:, settings:)
puts "Configuring user profile:"
puts "Profile: #{profile}"
puts "Preferences: #{preferences}"
puts "Settings: #{settings}"
end
# Hash of user configuration
user_configuration = {
profile: { username: 'johndoe', language: 'EN' },
preferences: { theme: 'dark', notifications: true },
settings: { privacy: 'high', location: 'off' }
}
# Using 2 splats to pass a hash
configure_user(**user_configuration) 👈
# This code will output:
Configuring user profile:
Profile: {:username=>"johndoe", :language=>"EN"}
Preferences: {:theme=>"dark", :notifications=>true}
Settings: {:privacy=>"high", :location=>"off"}