if

The if statement comes with the if, else if, and else clauses, just like most other languages. The one interesting feature that Go has is the ability to put a statement before the condition, creating temporary variables that are discarded after the if statement has completed.

This example demonstrates the various ways to use an if statement:

package main

import (
   "fmt"
   "math/rand"
)

func main() {
   x := rand.Int()

   if x < 100 {
      fmt.Println("x is less than 100.")
   }

   if x < 1000 {
      fmt.Println("x is less than 1000.")
   } else if x < 10000 {
      fmt.Println("x is less than 10,000.")
   } else {
      fmt.Println("x is greater than 10,000")
   }

   fmt.Println("x:", x)

   // You can put a statement before the condition 
   // The variable scope of n is limited
   if n := rand.Int(); n > 1000 {
      fmt.Println("n is greater than 1000.")
      fmt.Println("n:", n)
   } else {
      fmt.Println("n is not greater than 1000.")
      fmt.Println("n:", n)
   }
   // n is no longer available past the if statement
}