Maps

Beginner · Collections & Loops

A map is an unordered collection of key/value pairs: map[K]V. Create with make or a literal, read with m[k], and use the comma-ok form v, ok := m[k] to tell a missing key from a zero value. Delete with delete(m, k).

Resources

• Go blog: Go maps in action
• A Tour of Go: Maps
• Go by Example: Maps

Exercises

maps1 compile

Declare a map’s key and value types.

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Maps have types for both keys and values.

Define these types to make the code compile.

Indexing in maps is similar to setting values.

Check the spec for more info: https://go.dev/ref/spec#Map_types

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maps2 compile

Initialize a map with a literal.

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Similar to `maps1`, but you can initialize a new map in the same line using a different syntax.

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maps3 test

Look up the correct key in a map.

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Verify that the keys used to access map values match the keys defined in the phoneBook map.

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