循环小数转分数 | 莫烦Python

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循环小数转分数

作者: 白李子发布于: 2023-08-08 执行: 932 克隆: 0

这是我之前写的一个循环小数的类。注：循环小数的格式为0.{0}或者0.0{0}（分别为纯循环小数和混循环小数，大括号内的是循环节）

点击【Run】按钮将运行下方代码。可编辑、修改代码尝试新的运行逻辑。

class RecurringDecimal:
    def __init__(self,decimal:str):
        import re
        if bool(re.match(r"^\d+.\d*{\d+}$",decimal)):
            self.decimal=decimal
            self.integer=decimal.split(".")[0]
            this=decimal.split(".")[1]
            self.recurring=this[this.index("{")+1:len(this)-1]
            self.notRecurring=this[0:this.index("{")]
            if self.notRecurring=="":
                self.notRecurring=None
        else:
            raise RecurringDecimalError("你的循环小数格式不符合！！！")
    def convertToFraction(self,lowest=True):
        import math,re
        integer=self.integer
        if lowest:
            if self.notRecurring==None:
                numerator=self.recurring.lstrip("0")
                denominator="9"*len(self.recurring)
            else:
                try:
                    numerator=self.notRecurring+self.recurring+"-"+self.notRecurring
                    numerator=str(eval(numerator))
                except:
                    if bool(re.match(r"0+\d+",self.notRecurring+self.recurring)) and (not bool(re.match(r"0+\d+",self.notRecurring))):
                        numerator=(self.notRecurring+self.recurring).lstrip("0")+"-"+self.notRecurring
                    elif (not bool(re.match(r"0+\d+",self.notRecurring+self.recurring))) and bool(re.match(r"0+\d+",self.notRecurring)):
                        numerator=self.notRecurring+self.recurring+"-"+self.notRecurring.lstrip("0")
                    elif bool(re.match(r"0+\d+",self.notRecurring+self.recurring)) and bool(re.match(r"0+\d+",self.notRecurring)):
                        numerator=(self.notRecurring+self.recurring).lstrip("0")+"-"+self.notRecurring.lstrip("0")
                    numerator=str(eval(numerator))
                denominator="9"*len(self.recurring)+"0"*len(self.notRecurring)
            num=math.gcd(int(numerator),int(denominator))
            numerator=str(int(eval(numerator+"/"+str(num))))
            denominator=str(int(eval(denominator+"/"+str(num))))
        else:
            if self.notRecurring==None:
                numerator=self.recurring.lstrip("0")
                denominator="9"*len(self.recurring)
            else:
                try:
                    numerator=self.notRecurring+self.recurring+"-"+self.notRecurring
                    numerator=str(eval(numerator))
                except:
                    if bool(re.match(r"0+\d+",self.notRecurring+self.recurring)) and (not bool(re.match(r"0+\d+",self.notRecurring))):
                        numerator=(self.notRecurring+self.recurring).lstrip("0")+"-"+self.notRecurring
                    elif (not bool(re.match(r"0+\d+",self.notRecurring+self.recurring))) and bool(re.match(r"0+\d+",self.notRecurring)):
                        numerator=self.notRecurring+self.recurring+"-"+self.notRecurring.lstrip("0")
                    elif bool(re.match(r"0+\d+",self.notRecurring+self.recurring)) and bool(re.match(r"0+\d+",self.notRecurring)):
                        numerator=(self.notRecurring+self.recurring).lstrip("0")+"-"+self.notRecurring.lstrip("0")
                    numerator=str(eval(numerator))
                denominator="9"*len(self.recurring)+"0"*len(self.notRecurring)
        fraction=integer+"+"+numerator+"/"+denominator if integer!="0" else numerator+"/"+denominator
        return fraction
    def getIndexOf(self,index:int):
        if index>0:
            if self.notRecurring==None:
                return self.recurring[(index-1)%len(self.recurring)]
            else:
                if index<=len(self.notRecurring):
                    return self.notRecurring[index-1]
                else:
                    return self.recurring[(index-len(self.notRecurring)-1)%len(self.recurring)]
        else:
            raise RecurringDecimalError("位数不能为0或负数！！！")
    def __str__(self):
        return self.decimal
class RecurringDecimalError(Exception):
    def __init__(self,message):
        self.message=message

rd=RecurringDecimal(mofanpy["number"])
print(rd.convertToFraction())