tmrgo1/demo/govaluate/main.go

package main

import (
	"fmt"
	"github.com/Knetic/govaluate"
	"math"
	"strings"
)

func main() {
	//str := strings.ReplaceAll("(140<怀孕天数 && 怀孕天数<170?0.6/0.33:(169<怀孕天数 && 怀孕天数<198?1.1/0.5:(197<怀孕天数 && 怀孕天数<226?1.9/0.5:(225<怀孕天数 && 怀孕天数<254?3.1/0.5:(253<怀孕天数 && 怀孕天数<281?4.7/0.5:0)))))","怀孕天数","28")
	//str := `(温度>20?(0.085*Math.pow(体重,0.75)*(1-(温度-20)*0.005922)):(温度<5?(0.085*Math.pow(体重,0.75)/(1-(5-1*温度)*0.004644)):(0.085*Math.pow(体重,0.75))))`
	str := "(温度>20?(0.085*Math.pow(体重,0.75)*(1-(温度-20)*0.005922)):(温度<5?(0.085*Math.pow(体重,0.75)/(1-(5-1*温度)*0.004644)):(0.085*Math.pow(体重,0.75))))"
	//
	str = strings.ReplaceAll(str, "日增重", "1")
	str = strings.ReplaceAll(str, "体重", "640")
	str = strings.ReplaceAll(str, "怀孕天数", "200")
	str = strings.ReplaceAll(str, "产量", "30")

	str = strings.ReplaceAll(str, "乳脂率", "1")
	str = strings.ReplaceAll(str, "乳蛋白率", "1000")
	str = strings.ReplaceAll(str, "乳糖率", "1000")
	str = strings.ReplaceAll(str, "标准乳", "29.55")

	str = strings.ReplaceAll(str, "泌乳天数", "140")
	str = strings.ReplaceAll(str, "月龄", "1000")
	str = strings.ReplaceAll(str, "温度", "25")
	str = strings.ReplaceAll(str, "胎次", "1000")

	str = strings.ReplaceAll(str,"Math.pow","Mathpow")
	str = strings.ReplaceAll(str,"Math.round","Mathround")
	str = strings.ReplaceAll(str,"Math.log","Mathlog")
	str = strings.ReplaceAll(str,"Math.exp","Mathexp")
	//str = `(1000>30||50<100 ?    (50<25 ? 5:6)   : (1000>=25&&1000<=30 ? 7:1000<25 ? 8:"-"))`

	functions := map[string]govaluate.ExpressionFunction {
		"strlen": func(args ...interface{}) (interface{}, error) {
			length := len(args[0].(string))
			return (float64)(length), nil
		},
		"Mathpow" : func(args ...interface{}) (interface{}, error) {
			c:=math.Pow( args[0].(float64) , args[1].(float64))
			return (float64)(c), nil
		},
		"Mathround" : func(args ...interface{}) (interface{}, error) {
			c:=math.Round( args[0].(float64))
			return (float64)(c), nil
		},
		"Mathlog" : func(args ...interface{}) (interface{}, error) {
			c:=math.Log( args[0].(float64))
			return (float64)(c), nil
		},
		"Mathexp" : func(args ...interface{}) (interface{}, error) {
			c:=math.Exp( args[0].(float64))
			return (float64)(c), nil
		},
	}
	println(str)
	expression, err := govaluate.NewEvaluableExpressionWithFunctions(str, functions)
	if err != nil{
		println(err.Error())
	}

	result, err := expression.Evaluate(nil)
	if err != nil{
		println(err.Error())
	}
	fmt.Printf("== %+v\n", result)


}