数学函数

向上取整math.Ceil() 向下取整math.Floor()

//go没有其他语言得round函数，整数位得四舍五入简单版 func round(x float64){ return int(math.Floor(x + 0/5)) }

package main

import (
    "fmt"
    "github.com/shopspring/decimal"
)

/*
保有小数位得四舍五入
*/
func main() {
    v1, _ := decimal.NewFromFloat(9.824).Round(2).Float64()
    v2, _ := decimal.NewFromFloat(9.826).Round(2).Float64()
    v3, _ := decimal.NewFromFloat(9.8251).Round(2).Float64()
    fmt.Println(v1, v2, v3)

    v4, _ := decimal.NewFromFloat(9.815).Round(2).Float64()
    v5, _ := decimal.NewFromFloat(9.825).Round(2).Float64()
    v6, _ := decimal.NewFromFloat(9.835).Round(2).Float64()
    v7, _ := decimal.NewFromFloat(9.845).Round(2).Float64()
    fmt.Println(v4, v5, v6, v7)

    v8, _ := decimal.NewFromFloat(3.3).Round(2).Float64()
    v9, _ := decimal.NewFromFloat(3.3000000000000003).Round(2).Float64()
    v10, _ := decimal.NewFromFloat(3).Round(2).Float64()
    fmt.Println(v8, v9, v10)

    v11, _ := decimal.NewFromFloat(129.975).Round(2).Float64()
    v12, _ := decimal.NewFromFloat(34423.125).Round(2).Float64()
    fmt.Println(v11, v12)
}