time包中的Add和Sub的用法，Add用于计算某个时间之前和之后的时间点，Sub用于计算两个时间差
package main
import (
"fmt"
"strings"
"time"
)
func main() {
// Add 时间相加
now := time.Now()
// ParseDuration parses a duration string.
// A duration string is a possibly signed sequence of decimal numbers,
// each with optional fraction and a unit suffix,
// such as "300ms", "-1.5h" or "2h45m".
// Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h".
// 10分钟前
m, _ := time.ParseDuration("-1m")
m1 := now.Add(m)
fmt.Println(m1)
// 8个小时前
h, _ := time.ParseDuration("-1h")
h1 := now.Add(8 * h)
fmt.Println(h1)
// 一天前
d, _ := time.ParseDuration("-24h")
d1 := now.Add(d)
fmt.Println(d1)
printSplit(50)
// 10分钟后
mm, _ := time.ParseDuration("1m")
mm1 := now.Add(mm)
fmt.Println(mm1)
// 8小时后
hh, _ := time.ParseDuration("1h")
hh1 := now.Add(hh)
fmt.Println(hh1)
// 一天后
dd, _ := time.ParseDuration("24h")
dd1 := now.Add(dd)
fmt.Println(dd1)
printSplit(50)
// Sub 计算两个时间差
subM := now.Sub(m1)
fmt.Println(subM.Minutes(), "分钟")
sumH := now.Sub(h1)
fmt.Println(sumH.Hours(), "小时")
sumD := now.Sub(d1)
fmt.Printf("%v 天\n", sumD.Hours()/24)
}
func printSplit(count int) {
fmt.Println(strings.Repeat("#", count))
}
