### **百分比值(保留2位小數點)**
```go
/*
* Pct x,y百分比值
* github.com/shopspring/decimal
* patterns 百分比模式
* x=2 y=3
* patterns值 默認值:1
* 1(百分制) --> (x/y)*100 (66.666/100)*100 66.66
* 2(四舍五入百分制) --> (x/y)*100(四舍五入) 66.67
* 3(小數制) --> x/y 0.66
* 4(四舍五入小數制) --> x/y(四舍五入) 0.67
*/
func Pct(x, y float64, patterns ...int) float64 {
if y == 0 {
return 0
}
pattern := 1
if len(patterns) >= 1 {
pattern = patterns[0]
}
ratio := decimal.NewFromFloat(x).Div(decimal.NewFromFloat(y))
switch pattern {
case 1:
ratio = ratio.Mul(decimal.NewFromInt(100)).Truncate(2)
case 2:
ratio = ratio.Mul(decimal.NewFromInt(100)).Round(2)
case 3:
ratio = ratio.Truncate(2)
case 4:
ratio = ratio.Round(2)
}
v, _ := ratio.Float64()
return v
}
```
