What is “_,” (underscore comma) in a Go declaration?

Question

And I can\'t seem to understand this kind of variable declaration:

_, prs := m[\"example\"]

What exactly is \"_,\" doing and w

Answer 1

Basically, _, known as the blank identifier. In GO we can't have variables that are not being used.

As an instance when you iterating through an array if you are using value := range you don't want a i value for iterating. But if you omit the i value it will return an error. But if you declare i and didn't use it, it will also return an error.

Therefore, that is the place where we have to use _,.

Also it is used when you don't want a function's return value in the future.

Answer 2

The great use case for the unused variable is the situation when you only need a partial output. In the example below we only need to print the value (state population).

package main
import (
    "fmt"
)
func main() {
          statePopulations := map[string]int{
          "California": 39250017,
          "Texas":      27862596,
          "Florida":    20612439,
          }
          for _, v := range statePopulations {
          fmt.Println(v)
    }
}