Looping for range

Looping for range digunakan untuk mengulangi urutan pada value dengan tipe data string, array, slice, map dan channel.

Contoh code looping for range pada string

Looping di string di Golang menghasilkan value dengan tipe data rune bukan byte.

package main

import "fmt"

func main() {
	str := "Hello, world!"
	for i, c := range str {
		fmt.Printf("str[%d] = %c type %T\n", i, c, c)
	}
}

str[0] = H type int32
str[1] = e type int32
str[2] = l type int32
str[3] = l type int32
str[4] = o type int32
str[5] = , type int32
str[6] =   type int32
str[7] = w type int32
str[8] = o type int32
str[9] = r type int32
str[10] = l type int32
str[11] = d type int32
str[12] = ! type int32

Contoh code looping for range pada array

package main

import "fmt"
 
func main() {
    values := [7]int{1, 3, 5, 7, 9, 11, 13}
 
    for i, val := range values {
        fmt.Printf("value[%d] = %d \n", i, val)
    }
}

value[0] = 1 
value[1] = 3 
value[2] = 5 
value[3] = 7 
value[4] = 9 
value[5] = 11
value[6] = 13

Contoh code looping for range pada slice

package main

import "fmt"
 
func main() {
    values := []int{1, 3, 5, 7, 9, 11, 13}
 
    for i, val := range values {
        fmt.Printf("value[%d] = %d \n", i, val)
    }
}

value[0] = 1 
value[1] = 3 
value[2] = 5
value[3] = 7
value[4] = 9
value[5] = 11
value[6] = 13

Contoh code looping for range pada map

package main

import "fmt"
 
func main() {
    users := map[string]interface{}{
		"member_01" : "aliana",
		"member_02" : "dawam",
		"member_03" : "yusran",
	}
 
    for key, val := range users {
        fmt.Printf("value[%s] = %s \n", key, val)
    }
}

value[member_01] = aliana 
value[member_02] = dawam 
value[member_03] = yusran

Contoh code looping for range pada channel

package main

import (
    "fmt"
)

func main() {
    ch := make(chan int)

    go func() {
        for i := 0; i < 100; i++ {
			// channel in
            ch <- i
        }
		// channel must be close
		// if not will be deadlock
        close(ch)
    }()

	// channel out
    for v := range ch {
        fmt.Println(v)
    }
}

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Reference:

Golang, running for range loop on channel, how to continue execution of block having received next value from channel?Stack Overflow