Tour of Go 2.0

For

Go keeps it simple — there’s only for. No while, no do-while. Just for.

The basic for loop has three components, separated by semicolons:

  • init statement: runs once before the first iteration
  • condition expression: checked before every iteration
  • post statement: runs at the end of every iteration

The init statement is usually a short variable declaration. Variables declared there are scoped to the for block — they don’t leak out.

The loop stops as soon as the condition evaluates to false.

One thing to notice: unlike C, Java, or JavaScript, there are no parentheses around the three components. The braces {} are always required, though.

Give it a shot — run the example and change the condition or step to see what happens.

main.go ▶ Run in Playground 
package main

import "fmt"

func main() {
	sum := 0
	for i := 0; i < 10; i++ {
		sum += i
	}
	fmt.Println(sum)
}