Go by Example: For

for is Go’s only looping construct. Here are some basic types of for loops.

 
package main
 
import "fmt"
 
func main() {

The most basic type, with a single condition.

 
    i := 1
    for i <= 3 {
        fmt.Println(i)
        i = i + 1
    }

A classic initial/condition/after for loop.

 
    for j := 0; j < 3; j++ {
        fmt.Println(j)
    }

Another way of accomplishing the basic “do this N times” iteration is range over an integer.

 
    for i := range 3 {
        fmt.Println("range", i)
    }

for without a condition will loop repeatedly until you break out of the loop or return from the enclosing function.

 
    for {
        fmt.Println("loop")
        break
    }

You can also continue to the next iteration of the loop.

 
    for n := range 6 {
        if n%2 == 0 {
            continue
        }
        fmt.Println(n)
    }
}
 
$ go run for.go
1
2
3
0
1
2
range 0
range 1
range 2
loop
1
3
5

We’ll see some other for forms later when we look at range statements, channels, and other data structures.

Next example: If/Else.

by Mark McGranaghan and Eli Bendersky | source | license