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### GoLang Map

• date 29th May, 2021 |
• by Prwatech |

## Creating Maps in GoLang: Step-by-Step Tutorial

A Map is a type of data structure, it is a collection of unorder pairs of key-value. With the help of map we can easily do retrieve, update and insert operations.

#### Syntax:

var mymap map[keytype]valuetype

Use Case 1:

package main

import “fmt”

func main() {

var mymap map[int]int

if mymap == nil {

fmt.Println(“true”)

} else {

fmt.Println(“False”)

}

}

Output:

Use Case 2:

package main

import “fmt”

func main() {

var mymap map[int]int

if mymap == nil {

fmt.Println(“true”)

} else {

fmt.Println(“False”)

}

map2 := map[int]string{

10: “Prwatech”,11: “Bangalore”,

}

fmt.Println(“Map 2 value”, map2)

}

Output:

Use Case 3: Create a map using make() function.

package main

import “fmt”

func main() {

// Creating a map

// Using make() function

var map1 = make(map[int]string)

fmt.Println(map1)

// As we already know that make() function

/ always returns a map which is initialized

// So, we can add values in it

map1[1] = “Prwatech”

map1[2] = “Bangalore”

fmt.Println(map1)

}

Output:

Use Case 4: Adding new key elements and update operation:

package main

import “fmt”

// Main function

func main() {

// Creating and initializing a map

m_a_p := map[int]string{

90: “Prwatech”,

91: “Bangalore”,

92: “Big Data”,

}

fmt.Println(“Original map: “, m_a_p)

// Adding new key-value pairs in the map

m_a_p[93] = “Python”

m_a_p[94] = “Golang”

fmt.Println(“Map after adding new key-value pair:\n”, m_a_p)

// Updating values of the map

m_a_p[93] = “Gcp”

fmt.Println(“\nMap after updating values of the map:\n”, m_a_p)

}

Output:

Use Case 5:Retrieving values with the help of keys:

package main

import “fmt”

// Main function

func main() {

// Creating and initializing a map

m_a_p := map[int]string{

90: “Red”,

91: “Yellow”,

92: “Orange”,

93: “Blue”,

94: “White”,

}

fmt.Println(“Original map: “, m_a_p)

// Retrieving values with the help of keys

value_1 := m_a_p[90]

value_2 := m_a_p[93]

fmt.Println(“Value of key[90]: “, value_1)

fmt.Println(“Value of key[93]: “, value_2)

}

Output:

#### Use Case 6:Deleting keys

package main

import “fmt”

// Main function

func main() {

// Creating and initializing a map

m_a_p := map[int]string{

90: “Red”,

91: “Yellow”,

92: “Orange”,

93: “Blue”,

94: “White”,

}

fmt.Println(“Original map: “, m_a_p)

// Deleting keys

// Using delete function

delete(m_a_p, 90)

delete(m_a_p, 93)

fmt.Println(“Map after deletion: “, m_a_p)

}

Output:

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