for loop

C-style

Variables declared in for and if are local to their scope.

for x := 0; x < 3; x++ {
    fmt.Println("iteration", x)
}

Iterate over an object

You can use range to iterate over an array, a slice, a string, a map, or a channel.

range returns one (channel) or two values (array, slice, string and map).

Map of key-values pairs.

my_map := map[string]int{"one": 1, "two": 2, "three": 3}

for key, value := range my_map {
    fmt.Printf("key=%s, value=%d\n", key, value)
}

Slice

Unpack as index and value. Or use an underscore for index if you don’t need it.

my_slice = []string{"Bob", "Bill", "Joe"}

for _, name := range my_slice {
    fmt.Printf("Hello, %s\n", name)
}
// Bob
// Bill
// Joe

for i, v := range my_slice {
    fmt.Println(i, v)
}
// 0 Bob
// 1 Bill
// 2 Joe

while loop

Use for without anything after.

for { 
    // ...
}

Keywords

  • break
  • contine