我不能在 golang 中使用变量进行时间计算吗？

Question

我正在尝试计算 10 分钟前的时间。为什么我不能用变量进行这个计算（可用于 for 循环）。看 -package mainimport (    "fmt"    "time")func main() {    // the time now    fmt.Println(time.Now())    // the time 50 minutes ago - WORKS    diff := (60 - 10) * time.Minute    newTime := time.Now().Add(-diff)    fmt.Println(newTime)    // the time 50 minutes ago - DOESN'T WORKS!    i := 10    diff = (60 - i) * time.Minute    newTime = time.Now().Add(-diff)    fmt.Println(newTime)}为什么diff = (60 - i) * time.Minute不起作用？这是我得到的错误 -prog.go:20: invalid operation: (60 - i) * time.Minute (mismatched types int and time.Duration)去游乐场：https : //play.golang.org/p/TJ03K0ULg2

Answer 1

就像错误所说的那样，您的类型不匹配。将整数结果转换为 a time.Duration：

diff = time.Duration(60-i) * time.Minute

Answer 2

time.Duration实际上是类型int64，所以如果你想使用变量来制作你想要的东西，只需将变量声明为time.Duration，就像这样：

package main

import (

    "fmt"

    "time"

)

func main() {

    // the time now

    fmt.Println(time.Now())

    // the time 50 minutes ago - WORKS

    diff := (60 - 10) * time.Minute

    newTime := time.Now().Add(-diff)

    fmt.Println(newTime)

    // the time 50 minutes ago - DOESN'T WORKS!

    var i time.Duration

    diff = (60 - i) * time.Minute

    newTime = time.Now().Add(-diff)

    fmt.Println(newTime)

}