How to add a key to a map in Golang

In this tutorial, you will learn how you can add a key to a map in Golang so that it does not override the existing key's value

The easiest way to add a new key to a map in Golang is to simply do

m := make(map[string]int)
m["apple"] = 1

However, it might override the existing key's value if the key you want to add is already present in the map

m := make(map[string]int)
m["apple"] = 1
m["apple"] = 2 //overrides the previous value of "apple"

Therefore, to be on the safer side, you can check if the key exists in a map before adding the key to the map.

package main

import "fmt"

func main () {
  m := make(map[string]int)
  m["apple"] = 1
  m["mango"] = 2
  
  if val, isKeyExists := m["blueberry"]; isKeyExists {
    fmt.Printf("key exists: value [%d]\n", val)
  } else {
    m["blueberry"] = 3
  }
  fmt.Printf("%v", m)
}

Related Solutions

• How to get a slice of keys from a map in Golang

• How to remove a key from a map in Golang

• How to check if a map is empty in Golang

• How to create a map in Golang