Go for loop Example

golang-for-loop

This golang tutorial help to understand loop statement under the hood of Golang. The loop is used to execute a block of code repeatedly.Go has only one looping construct, the for loop.The Golang doesn’t have while or do-while loops which are present in other programming languages.

The Go for loop has three components separated by semicolons which are following.

  • The init statement: The init statement executed before the first iteration. This step allows us to declare and initialize any for loop control variables.
  • The condition expression: This statement is evaluated before every iteration occur. If a condition is true, the body of the loop is executed. If the condition is false, then the body of the loop does not execute, and the control flow jumps to a next statement.
  • The post statement:This statement executed at the end of every iteration.

The syntax :

for [condition |  ( init; condition; increment ) | Range] {
   body
}

The simple example using go for loop

/* main.go */

package main

func main() {
   names := []string{"Adam", "Sam", "Daniel"}

   for i := 0; i < len(names); i++ {
    println(i, names[i])
   }
}

As You can see that, There is no parentheses are required to surround for loop statement, but the braces { } are required to execute code block.

Run the golang code –
$go run main.go

Output :

0 Adam<br>
1 Sam<br>
2 Daniel

We can also use the range function with for loop. Let’s see the following example.

/* main.go */
package main

func main() {
   names := []string{"Adam", "Sam", "Daniel"}

   for i, name := range names {
    println(i, name)
   }
}

The range is used to iterate on each element of the slice in Go.

Run the golang code –
$go run main.go

Output :

 0 Adam
 1 Sam
 2 Daniel