How to check if a value exists in a map in Golang

In this shot, we will learn to check if a value exists in a map using Golang.

No built-in function checks if a value exists in a map in Golang.

So, we will use the following approach to check if a value exists in a map:

Traverse through the entire map.
Check if the present value is equal to the value the user wants to check.
- If it is equal and is found, print the value.
- Otherwise, print that the value is not found in the map.

package main
//program execution starts here
func main(){
  //declare a map
  students := map[string]int{
    "john": 10,
    "james": 12,
    "mary":13,
  }
  
  //provide user value 
  var userValue = 10
  //call function and proceed according to return
  if checkForValue(userValue,students){
    //executes if a value is present in the map
    println("Value found")
  }else{
    //executes if a value is NOT present in the map
    println("Value NOT found in the map")
  }
  
  
}
//function to check if a value present in the map
func checkForValue(userValue int, students map[string]int)bool{
  //traverse through the map
  for _,value:= range students{
    //check if present value is equals to userValue
    if(value == userValue){
      //if same return true
      return true
    }
  }
  //if value not found return false
  return false
}

Explanation

We declare and initialize a map students, with the key as the student’s name and the value as their age.
Line 14: We provide user input.
Line 30: We declare the function that accepts the userValue and students as parameters and returns a boolean value.
- Line 33: We traverse through the map, students, and check if the present value equals the userValue. If it is equal, return true.
- Line 44: If the userValue is not found in the map after traversing, return false.
Line 17: We call the checkForValue function and use an if statement to check if the returned value is true or false. We then display the output accordingly.

How to check if a value exists in a map in Golang

Example

Code

Explanation