Mutations on Maps

Maps can be mutated.

m := map[string]int{
  "John": 37,
  "Mary": 21,
}

Insert an element

m[key] = elem

// example
m["Amanuel"] = 20

fmt.Println(m) // map[Amanuel:20 John:37 Marry:21]

Get an element

elem := m[key]

// example
ageJohn := m["John"]

fmt.Println(ageJohn) // 37

Delete an element

delete(m, key)

// example
delete(m, "John")

fmt.Println(m) // map[Amanuel:20 Marry:21]

Check if a key exists

elem, ok := m[key]

If key is in m, then ok is true. If not, ok is false.

If key is not in the map, then elem is the zero value for the map's element type.