# Keyword Lists A `Keyword` list is a list of key-value pairs that has three special characteristics: 1. Keys must be `Atom`s. 1. The key-value pairs are ordered. 1. Keys can be duplicated. Here's how to use keyword lists: ```elixir keyword = [name: "Peter", age: 32, name: "Pietah"] # Access an element using the bracket notation keyword[:age] # => 32 # But it will only return the first key keyword[:name] # => "Peter" # You can also use a helper function Keyword.get(keyword, :age) # => 32 # Replace an existing value with a new one Keyword.replace(keyword, :age, 33) # => [name: "Peter", age: 33, name: "Pietah"] # But when you update a duplicate key, it will only keep the new value and remove the rest Keyword.replace(keyword, :name, "Pieter") # => [name: "Pieter", age: 32] # Delete all pairs that have a given key Keyword.delete(keyword, :name) # => [age: 32] # Only delete the first occurrence Keyword.delete_first(keyword, :name) # => [age: 32, name: "Pietah"] ```