python十进制浮点数（小数）转换为二进制

比眉伴天荒 2022-05-24 02:48 485阅读 0赞

最近学习计算机系统概论，经常需要将十进制的浮点数转换为二进制的形式，加之有相关作业，写个代码与大家分享。逻辑稍有混乱，不过还是很好用的

#传入一个浮点型字符串和有效数字位数
    def fraction_to_binary(fraction_string, significant_binary_digits):
        def print_binary(number_string, fraction_length):
            dotleft=""
    
            netative="+"
            if float(number_string)<0:
                netative="-"
                
    
            if "." in number_string:
                a,b=number_string.split(".")
            else:
                a=number_string
            a=int(a)
            if a<0:
                a=-a
            result=[]
            def dec2bin(number):
                if number==1:
                    result.insert(0,"1")
                elif number==0:
                    result.insert(0,"0")
                else:
                    if number%2==0:
                        result.insert(0,"0")
                        dec2bin(number//2)
                    else:
                        result.insert(0,"1")
                        dec2bin(number//2)
            dec2bin(int(a))
            for i in result:
                dotleft+=i
            #print(dotleft)
            if "." in  number_string:
    
                number=float("0."+b)
                count=0
                dotright=""
                number=float("0."+b)
                while count<fraction_length:
                    if number*2>=1:
                        dotright=dotright+"1"
                        number=number*2-1
                        count+=1
                    else:
                        number*=2
                        dotright=dotright+"0"
                        count+=1
            else:
                dotright="0"*fraction_length
            temp=netative+dotleft+"."+dotright
            return temp[1:]
        
        answer=print_binary(fraction_string, 15)
        first_1=answer.index("1")
        liebiao=list(answer[answer.index(".")+1:first_1+significant_binary_digits+1])
        #print(liebiao)
        #打印列表
        for i in liebiao:
            print(i,end=" ")
        print()
        #列表打印完毕
    
        #处理进位
        woshigetemp=-1
        liebiao.insert(0,"0")
        if liebiao[-1]=="1":
    
            while 12138:
                    if liebiao[woshigetemp]=="0":
                    
                    
                        liebiao[woshigetemp]="1"
                        break
                    elif liebiao[woshigetemp]==".":
                        pass
                    
                    else:
                        liebiao[woshigetemp]="0"
                    
                    woshigetemp-=1
        #print(liebiao[:-1])
        ###
    
        ###打印
        print_str=""
        #liebiao=liebiao[:-1]
        liebiao=liebiao[:liebiao.index("1")+significant_binary_digits]
        #print(liebiao)
        liebiao.insert(1,".")
        for i in liebiao:
            print_str+=i
        
        print(print_str)