go | switch/case、array、slices、range、functions

go 的一些例子

go 的 switch–case
switch–case 走的逻辑 或者说流程 和 c/c++ 是一样的，自上而下，判断case 是否满足条件
如果满足条件，进入相应的语句，如果不满足，走 default

package main

import (
	"fmt"
	"time"
)

func main() {
   
	fmt.Println("Hello, 世界")

	i := 5
	fmt.Println("write ", i, " as ")
	switch i {
   
	case 1:
		fmt.Print("one")
	case 2:
		fmt.Print("two")
	case 3:
		fmt.Print("three")
	default:
		fmt.Print("else")
	}

	switch time.Now().Weekday() {
   
	case time.Saturday, time.Sunday:
		fmt.Println(" this is weekend", time.Now().Weekday())
	default:
		fmt.Println(" this is weekday", time.Now().Weekday())
	}
	t := time.Now()
	switch {
   
	case t.Hour() < 12:
		fmt.Println("this is before noon", time.Now().Hour())
	default:
		fmt.Println("this is after noon", time.Now().Hour())
	}
	whatAmI := func(i interface{
   }) {
   
		switch t := i.(type) {
   
		case bool:
			fmt.Println("this is a bool")
		case int:
			fmt.Println("this is a int")
		case string:
			fmt.Println("this is a string")
		// 为什么 吧 default 写在最后？因为 t 会依次从bool  到 string 比较, 不满足当前的，就比较下一个，直到 default ，如果说 case  无穷， 如果一直没匹配到，那么这就是一个死循环了
		default:
			fmt.Println("Don't know this type", t)
		}
	}
	whatAmI(true)
	whatAmI(123)
	whatAmI("zhangbuda")
	whatAmI(2.22)

}

# 输出结果
Hello, 世界
write  5  as 
else this is weekday Tuesday
this is after noon 23
this is a bool
this is a int
this is a string
Don't know this type 2.22

这里插播一下 关于 go 获取当前时间

import