Codecademy Logo

Learn Go: Maps

Print Cheatsheet

Go Map Creation

In Go, an empty map can be created using make. The type of keys and values are specified.

variableName := make(map[keyType]valueType)

Go Map Initialization

In Go, a map can be intialized with key:value data.

variableName := map[keyType]valueType{
key1, value1,
key2, value2,
key3, value3,
}

Go Map Access

In Go, any value can be accessed by specifying the associated key. A second value can be returned to check if the key is in the map.

value := yourMap[key]
checkedValue,isFound := yourMap[key]

Go Adding to a Map

In Go, additional key:value pairs can be added to the map by specifying the new key and its value.

yourMap[newKey] = newValue

Go Updating a Map

In Go, existing values can be updated by specifying a key and an updated value.

yourMap[existingKey] = newValue

Go Map Deletions

In Go, key:value pairs can be removed with the delete syntax where a map and key are specified.

delete(yourMap, keyValueToDelete)

Go Maps

In Go, a map is an unordered collection of key:value pairs. Keys are used as a way to access a value. Maps are used to associate one piece of data with another.

Example use cases include:

  • Counting the number of times unique names appear in a list.
  • Mapping simple identifiers, such as an employee id, to related values.
  • Anytime we need to associate any piece of data with another!