How to Check if a Value Exists in a Map in Go

How to Check if a Value Exists in a Map in Go ?

Answer

To check if a value exists in a map in Go, you need to iterate through the map and compare each value. This approach helps determine if a specific value is present in the map.

✐ Examples

1 Checking if a Value Exists Using Loop

We can check if a value exists in a map in Go by iterating through the map and comparing each value to the specified value.

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 declare a boolean variable valueExists and initialize it to false. This variable will be used to indicate if the value is found in the map.
We use a for loop to iterate through each key-value pair in the map. Inside the loop, we compare the value of the current pair with the specified value.
If the value matches the specified value, we set valueExists to true and break the loop.
We print the result to the console using the fmt.Println function.

Go Program

package main

import "fmt"

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

    // Check if a value exists using loop
    valueExists := false
    for _, value := range myMap {
        if value == 2 {
            valueExists = true
            break
        }
    }

    // Print the result
    fmt.Println("Does value 2 exist?", valueExists)
}

Output

Does value 2 exist? true

2 Checking if a Value Does Not Exist Using Loop

We can check if a value does not exist in a map in Go by iterating through the map and comparing each value to the specified value.

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 declare a boolean variable valueExists and initialize it to false. This variable will be used to indicate if the value is found in the map.
We use a for loop to iterate through each key-value pair in the map. Inside the loop, we compare the value of the current pair with the specified value.
If the value matches the specified value, we set valueExists to true and break the loop.
We print the result to the console using the fmt.Println function.

Go Program

package main

import "fmt"

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

    // Check if a value does not exist using loop
    valueExists := false
    for _, value := range myMap {
        if value == 4 {
            valueExists = true
            break
        }
    }

    // Print the result
    fmt.Println("Does value 4 exist?", valueExists)
}

Output

Does value 4 exist? false

3 Checking Multiple Values Using Loop

We can check if multiple values exist in a map in Go by iterating through the map and comparing each value to the specified values.

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 declare two boolean variables valueExistsOne and valueExistsFour, and initialize them to false. These variables will be used to indicate if the values are found in the map.
We use a for loop to iterate through each key-value pair in the map. Inside the loop, we compare the value of the current pair with the specified values.
If the value matches one of the specified values, we set the corresponding boolean variable to true and break the loop.
We print the results to the console using the fmt.Println function.

Go Program

package main

import "fmt"

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

    // Check if multiple values exist using loop
    valueExistsOne := false
    valueExistsFour := false
    for _, value := range myMap {
        if value == 1 {
            valueExistsOne = true
        }
        if value == 4 {
            valueExistsFour = true
        }
    }

    // Print the results
    fmt.Println("Does value 1 exist?", valueExistsOne)
    fmt.Println("Does value 4 exist?", valueExistsFour)
}

Output

Does value 1 exist? true
Does value 4 exist? false

Summary

In this tutorial, we learned How to Check if a Value Exists in a Map in Go language with well detailed examples.

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How to Check if a Value Exists in a Map in Go