Delete Key from a map in Go

Remove an item from map in Go

Let us look at removing an item from the map using the delete() function with an example.

Syntax

The Syntax for delete() function is:

delete(map,key)

Parameters

The delete() function accepts two parameters:

• map: name of the map
• key: the key of the element that needs to be deleted

Return Value

The delete() function does not return anything as the delete happens in the original map.

Example: Delete an item from the map in golang

In our example, we have a list of cars where the car name is a key, and the quantity available is the value.

//Program to remove a key from the map

package main

import "fmt"

func main() {

    // create a map
  	cars := map[string]int{
		"Audi":       1250,
		"Ford":       500,
		"Volkswagen": 700,
		"BMW":        400}

    fmt.Println("Before Deletion:", cars)

    // Delete an element using it's key
    delete(cars, "Ford")

    fmt.Println("After Deletion:", cars)
}

Output

Before Deletion: map[Audi:1250 BMW:400 Ford:500 Volkswagen:700]
After Deletion: map[Audi:1250 BMW:400 Volkswagen:700]

In the above Program -

• We have defined a map named cars, and the car name is the key and quantities as values inside the map.
• We are removing an item with the key nameFordfrom the cars map by passing the map name and key as an argument to the delete() function.
• We display the map after deleting an item from the map.

Example 2: Remove a key from the map A better way to write a code that don't create a panic is to check if the key exists in the first place, as shown below.

// Program to remove a key from the map

package main

import "fmt"

func main() {

	// create a map
	cars := map[string]int{
		"Audi":       1250,
		"Ford":       500,
		"Volkswagen": 700,
		"BMW":        400}

	fmt.Println("Before Deletion:", cars)

	if _, ok := cars["ford"]; ok {
		// Delete an element using it's key
		delete(cars, "ford")
	} else {
		fmt.Println("Could not find the key in a map")
	}

	fmt.Println("After Deletion:", cars)
}

Output

Before Deletion: map[Audi:1250 BMW:400 Ford:500 Volkswagen:700]
Could not find the key in a map
After Deletion: map[Audi:1250 BMW:400 Ford:500 Volkswagen:700]

Note: The key name is case-sensitive when passing to the delete() function.