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How to Add a Key-Value Pair to a Map in Go

How to Add a Key-Value Pair to a Map in Go ?

Answer

To add a key-value pair to a map in Go, you can use the subscript operator.


✐ Examples

1 Adding a Key-Value Pair Using Subscript Operator

We can add a key-value pair to a map in Go using the subscript operator, which adds an element with a specific key and value to the map.

For example,

  1. 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.
  2. We use the subscript operator to add a new key-value pair to the map. The subscript operator allows us to specify the key and assign a value to it.
  3. 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,
    }

    // Add a key-value pair using subscript operator
    myMap["four"] = 4

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

Output

one: 1
two: 2
three: 3
four: 4

2 Adding Multiple Key-Value Pairs Using Subscript Operator

We can add multiple key-value pairs to a map in Go using the subscript operator.

For example,

  1. 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.
  2. We use the subscript operator to add multiple new key-value pairs to the map. The subscript operator allows us to specify the keys and assign values to them.
  3. 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,
    }

    // Add multiple key-value pairs using subscript operator
    myMap["four"] = 4
    myMap["five"] = 5

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

Output

one: 1
two: 2
three: 3
four: 4
five: 5

Summary

In this tutorial, we learned How to Add a Key-Value Pair to a Map in Go language with well detailed examples.


More Go Maps Tutorials

  1. How to create an Empty Map in Go ?
  2. How to create a Map with Initial Key-Value Pairs in Go ?
  3. How to Print a Map in Go ?
  4. How to Add a Key-Value Pair to a Map in Go ?
  5. How to Set a Default Value for a Key in a Map in Go ?
  6. How to Update the Value for a Key in a Map in Go ?
  7. How to Check if a Map is Empty in Go ?
  8. How to Check if a Key Exists in a Map in Go ?
  9. How to Check if a Value Exists in a Map in Go ?
  10. How to Get the Value Associated with a Key in a Map in Go ?
  11. How to Remove a Key-Value Pair from a Map in Go ?
  12. How to Remove Key-Value Pairs from a Map Based on Values in Go ?
  13. How to Clear All Key-Value Pairs from a Map in Go ?
  14. How to Iterate Over Keys in a Map in Go ?
  15. How to Iterate Over Values in a Map in Go ?
  16. How to Iterate Over Entries (Key-Value Pairs) in a Map in Go ?
  17. How to Get the Size (Number of Key-Value Pairs) of a Map in Go ?
  18. How to Convert a Map to an Array of Keys in Go ?
  19. How to Convert a Map to an Array of Values in Go ?
  20. How to Convert a Map to an Array of Key-Value Pairs in Go ?
  21. How to Merge Two Maps in Go ?
  22. How to Copy a Map in Go ?
  23. How to Check if Two Maps are Equal in Go ?
  24. How to Sort a Map by Keys in Go ?
  25. How to Sort a Map by Values in Go ?
  26. How to Filter a Map Based on Keys in Go ?
  27. How to Filter a Map Based on Values in Go ?
  28. How to Reduce Values in a Map to a Single Value in Go ?
  29. How to Convert an Array of Key-Value Pairs to a Map in Go ?
  30. How to Convert a Map to a JSON String in Go ?
  31. How to Convert a JSON String to a Map in Go ?
  32. How to Swap Keys and Values in a Map in Go ?
  33. How to Create a Map of Maps in Go ?
  34. How to Iterate Over a Map of Maps in Go ?