for is the only loop statement in go, so a basic loop implementation could look like this:

// like if, for doesn't use parens either.
// variables declared in for and if are local to their scope.
for x := 0; x < 3; x++ { // ++ is a statement.
    fmt.Println("iteration", x)
}

// would print:
// iteration 0
// iteration 1
// iteration 2

Breaking out of the loop and continuing to the next iteration is also supported in Go, like in many other languages:

for x := 0; x < 10; x++ { // loop through 0 to 9
    if x < 3 { // skips all the numbers before 3
        continue
    } 
    if x > 5 { // breaks out of the loop once x == 6
        break
    }
    fmt.Println("iteration", x)
}

// would print:
// iteration 3
// iteration 4
// iteration 5

The break and continue statements additionally accept an optional label, used to identify outer loops to target with the statement:

OuterLoop:
for {
    for {
        if allDone() {
            break OuterLoop
        }
        if innerDone() {
            continue OuterLoop
        }
        // do something
    }
}

The for keyword is also used for conditional loops, traditionally while loops in other programming languages.

package main

import (
    "fmt"
)

func main() {
    i := 0
    for i < 3 { // Will repeat if condition is true
        i++
        fmt.Println(i)
    }
}

play it on playground

Will output:

1
2
3

infinite loop:

for {
    // This will run until a return or break.
}

Simple form using one variable:

for i := 0; i < 10; i++ {
    fmt.Print(i, " ")
}

Using two variables (or more):

for i, j := 0, 0; i < 5 && j < 10; i, j = i+1, j+2 {
    fmt.Println(i, j)
}

Without using initialization statement:

i := 0
for ; i < 10; i++ {
    fmt.Print(i, " ")
}

Without a test expression:

for i := 1; ; i++ {
    if i&1 == 1 {
        continue
    }
    if i == 22 {
        break
    }
    fmt.Print(i, " ")
}

Without increment expression:

for i := 0; i < 10; {
    fmt.Print(i, " ")
    i++
}

When all three initialization, test and increment expressions are removed, the loop becomes infinite:

i := 0
for {
    fmt.Print(i, " ")
    i++
    if i == 10 {
        break
    }
}

This is an example of infinite loop with counter initialized with zero:

for i := 0; ; {
    fmt.Print(i, " ")
    if i == 9 {
        break
    }
    i++
}

When just the test expression is used (acts like a typical while loop):

i := 0
for i < 10 {
    fmt.Print(i, " ")
    i++
}

Using just increment expression:

i := 0
for ; ; i++ {
    fmt.Print(i, " ")
    if i == 9 {
        break
    }
}

Iterate over a range of values using index and value:

ary := [5]int{0, 1, 2, 3, 4}
for index, value := range ary {
    fmt.Println("ary[", index, "] =", value)
}

Iterate over a range using just index:

for index := range ary {
    fmt.Println("ary[", index, "] =", ary[index])
}

Iterate over a range using just index:

for index, _ := range ary {
    fmt.Println("ary[", index, "] =", ary[index])
}

Iterate over a range using just value:

for _, value := range ary {
    fmt.Print(value, " ")
}

Iterate over a range using key and value for map (may not be in order):

mp := map[string]int{"One": 1, "Two": 2, "Three": 3}
for key, value := range mp {
    fmt.Println("map[", key, "] =", value)
}

Iterate over a range using just key for map (may be not in order):

for key := range mp {
    fmt.Print(key, " ") //One Two Three
}

Iterate over a range using just key for map (may be not in order):

for key, _ := range mp {
    fmt.Print(key, " ") //One Two Three
}

Iterate over a range using just value for map (may be not in order):

for _, value := range mp {
    fmt.Print(value, " ") //2 3 1
}

Iterate over a range for channels (exits if the channel is closed):

ch := make(chan int, 10)
for i := 0; i < 10; i++ {
    ch <- i
}
close(ch)

for i := range ch {
    fmt.Print(i, " ")
}

Iterate over a range for string (gives Unicode code points):

utf8str := "B = \u00b5H" //B = µH
for _, r := range utf8str {
    fmt.Print(r, " ") //66 32 61 32 181 72
}
fmt.Println()
for _, v := range []byte(utf8str) {
    fmt.Print(v, " ") //66 32 61 32 194 181 72
}
fmt.Println(len(utf8str)) //7

as you see utf8str has 6 runes (Unicode code points) and 7 bytes.

package main

import(
    "fmt"
    "time"
)

func main() {
    for _ = range time.Tick(time.Second * 3) {
        fmt.Println("Ticking every 3 seconds")
    }
}