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A Keyword list is a list of key-value pairs that has three special characteristics:

  1. Keys must be Atoms.
  2. The key-value pairs are ordered.
  3. Keys can be duplicated.

Here's how to use keyword lists:

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"]