kc3-lang/kc3/doc/1_KC3/1.21_Map.en.md
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Hash : 0310c9c5
Author :
Thomas de Grivel
Date : 2025-04-02T15:39:48
doc: fix access calls in examples.
1.21 Map
KC3 maps are like Elixir maps, they are key-values enclosed in %{} :
ikc3> a = %{id: 1, title: "My title", message: "Hello, world !"}
%{id: 1,
title: "My title",
message: "Hello, world !"}Destructuring works with maps to extract values :
ikc3> %{id: id, title: "My title", message: message} = ^ a
%{id: 1,
title: "My title",
message: "Hello, world !"}
ikc3> id
1
ikc3> message
"Hello, world !"
You can use the dot syntax to access map values from a Sym key :
ikc3> a = %{id: 1, title: "My title", message: "Hello, world !"}
%{id: 1,
title: "My title",
message: "Hello, world !"}
ikc3> a.id
1
ikc3> a.message
"Hello, world !"The bracket syntax allows you to query any key type :
ikc3> a[:id]
1
ikc3> a[:message]
"Hello, world !"
You can also use the KC3.access function for the same result :
ikc3> a = %{id: 1, title: "My title", message: "Hello, world !"}
%{id: 1,
title: "My title",
message: "Hello, world !"}
ikc3> access(a, [:id])
1
ikc3> access(a, [:message])
"Hello, world !"To update an existing map you can use Map.put like this :
ikc3> a = %{id: 1, title: "My title"}
%{id: 1,
title: "My title"}
ikc3> a = Map.put(a, :message, "Hello, world !")
%{id: 1,
title: "My title",
message: "Hello, world !"}Top : KC3 documentation
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doc/1_KC3/1.21_Map.en.md
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# 1.21 Map KC3 maps are like Elixir maps, they are key-values enclosed in `%{}` : ```elixir ikc3> a = %{id: 1, title: "My title", message: "Hello, world !"} %{id: 1, title: "My title", message: "Hello, world !"} ``` Destructuring works with maps to extract values : ```elixir ikc3> %{id: id, title: "My title", message: message} = ^ a %{id: 1, title: "My title", message: "Hello, world !"} ikc3> id 1 ikc3> message "Hello, world !" ``` You can use the dot syntax to access map values from a `Sym` key : ```elixir ikc3> a = %{id: 1, title: "My title", message: "Hello, world !"} %{id: 1, title: "My title", message: "Hello, world !"} ikc3> a.id 1 ikc3> a.message "Hello, world !" ``` The bracket syntax allows you to query any key type : ```elixir ikc3> a[:id] 1 ikc3> a[:message] "Hello, world !" ``` You can also use the `KC3.access` function for the same result : ```elixir ikc3> a = %{id: 1, title: "My title", message: "Hello, world !"} %{id: 1, title: "My title", message: "Hello, world !"} ikc3> access(a, [:id]) 1 ikc3> access(a, [:message]) "Hello, world !" ``` To update an existing map you can use Map.put like this : ```elixir ikc3> a = %{id: 1, title: "My title"} %{id: 1, title: "My title"} ikc3> a = Map.put(a, :message, "Hello, world !") %{id: 1, title: "My title", message: "Hello, world !"} ``` --- Top : [KC3 documentation](/doc/)