learn/golang-learn/48-range/range.go

package main

import (
	"fmt"
	"strings"
)

var pow = []int{1, 2, 4, 8, 16, 32, 64, 128}

var str = "hello"

var map1 = make(map[int]float32)

func main() {
	// 遍历数组
	for i, v := range pow {
		fmt.Printf("2**%d = %d\n", i, v)
	}

	fmt.Printf("\n%s\n\n", strings.Repeat("*", 100))

	// 遍历字符串
	for i, v := range str {
		fmt.Printf("遍历字符串, 下标 %d, 值 %c\n", i, v)
	}

	map1[1] = 1.0
	map1[2] = 2.0
	map1[3] = 3.0
	map1[4] = 4.0

	fmt.Printf("\n%s\n\n", strings.Repeat("*", 100))

	// 遍历 map, 读取 k, v
	for k, v := range map1 {
		fmt.Printf("k = %d - v = %f\n", k, v)
	}

	// 遍历 map, 只读 k
	for k := range map1 {
		fmt.Printf("k = %d\n", k)
	}

	// 遍历 map, 只读 v
	for _, v := range map1 {
		fmt.Printf("v = %f\n", v)
	}

	fmt.Printf("\n%s\n\n", strings.Repeat("*", 100))

	// 遍历 channel
	ch_length := 10
	ch := make(chan int, ch_length)
	for i := 0; i < ch_length; i++ {
		ch <- i
	}
	close(ch)
	for v := range ch {
		fmt.Println(v)
	}
}