How to Update the Value for a Key in a Map in Go - Step by Step Examples

How to Update the Value for a Key in a Map in Go ?

Answer

To update the value for a key in a map in Go, you can use the subscript operator. This method allows you to modify the value associated with a specific key directly.

✐ Examples

1 Updating the Value Using Subscript Operator

We can update the value for a key in a map in Go using the subscript operator, which allows us to modify the value associated with a specific key directly.

For example,

We start by declaring and initializing a map named myMap with some key-value pairs. In this example, the map has string keys and integer values.
We use the subscript operator to update the value for a specific key in the map. The subscript operator allows us to assign a new value to the key.
We print the updated map to the console using a for range loop and the fmt.Printf function.

Go Program

package main

import "fmt"

func main() {
    // Declare and initialize a map
    myMap := map[string]int{
        "one": 1,
        "two": 2,
        "three": 3,
    }

    // Update the value using subscript operator
    myMap["two"] = 22

    // Print the updated map
    for key, value := range myMap {
        fmt.Printf("%s: %d\n", key, value)
    }
}

Output

one: 1
two: 22
three: 3

2 Updating the Value Conditionally Using if Statement

We can update the value for a key in a map in Go using an if statement to check if the key exists and then modify the value associated with it directly.

For example,

We start by declaring and initializing a map named myMap with some key-value pairs. In this example, the map has string keys and integer values.
We use an if statement to check if the key exists in the map. If the key exists, we update the value using the subscript operator.
We print the updated map to the console using a for range loop and the fmt.Printf function.

Go Program

package main

import "fmt"

func main() {
    // Declare and initialize a map
    myMap := map[string]int{
        "one": 1,
        "two": 2,
        "three": 3,
    }

    // Update the value conditionally using if statement
    if _, exists := myMap["two"]; exists {
        myMap["two"] = 22
    }

    // Print the updated map
    for key, value := range myMap {
        fmt.Printf("%s: %d\n", key, value)
    }
}

Output

one: 1
two: 22
three: 3

3 Updating Multiple Values Using Subscript Operator

We can update multiple values for keys in a map in Go using the subscript operator.

For example,

We start by declaring and initializing a map named myMap with some key-value pairs. In this example, the map has string keys and integer values.
We use the subscript operator to update the values for specific keys in the map. The subscript operator allows us to assign new values to the keys.
We print the updated map to the console using a for range loop and the fmt.Printf function.

Go Program

package main

import "fmt"

func main() {
    // Declare and initialize a map
    myMap := map[string]int{
        "one": 1,
        "two": 2,
        "three": 3,
    }

    // Update multiple values using subscript operator
    myMap["two"] = 22
    myMap["three"] = 33

    // Print the updated map
    for key, value := range myMap {
        fmt.Printf("%s: %d\n", key, value)
    }
}

Output

one: 1
two: 22
three: 33

Summary

In this tutorial, we learned How to Update the Value for a Key in a Map in Go language with well detailed examples.

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How to Update the Value for a Key in a Map in Go - Step by Step Examples