使用Python二进制与十进制之间的转化，可以操作浮点数！

PS: 本来贴在forum.ubuntu.org.cn里。贴回来只是为了集中下资料。

 

 

我自己写的，算法就是课本上讲的转化的方式。

 

代码如下：

# coding=UTF-8from decimal import Decimaldef mybin(float, bit = 10): """ 这个程序用来将十进制数转化为二进制数,也可以转化浮点数 用法: mybin(float, bit=10) float是指要转化的十进制数，可以为浮点数 bit是用来指定小数点后面的位数，默认为10位。 函数返回字符串 """ ## 看数据是否有效 #import types #if type(float) is not types.IntType and type(float) is not types.FloatType: #print "Error,Please check your input./n" #return False # 检测极性 negative = 0 if float < 0: negative = 1 float = -1 * float integer = int(float) # 整数部分 decimal = Decimal(str(float)) - integer # 小数部分 integer_convert = "" # 转化后的整数部分 decimal_convert = "" # 转化后的小数部分 binary = "" # 最后的二进制数 if integer == 0: binary = "0" else: while integer != 0: result = int(integer % 2) integer = integer / 2 integer_convert = str(result) + integer_convert if decimal == 0: binary = integer_convert else: i = 0 while decimal != 0 and i < bit: result = int(decimal * 2) decimal = decimal * 2 - result decimal_convert = decimal_convert + str(result) i = i + 1 binary = integer_convert + '.' + decimal_convert if negative == 1: binary = '-' + binary return binarydef mydec(binary): """ 将二进制数变成十进制数，包括浮点数 用法：mydec(binary) binary是一个字符型二进制数，可以是浮点数 返回一个浮点数或者整数 """ ## 检测数据有效性 #if binary.find('-') not in [-1,0]: #print binary + "/t>>>/t" + "Error with negative symbol's place./n" #return False #elif binary.find('.') != binary.rfind('.') or binary[0] == '.' or binary[-1] == '.' or (binary.find('-') == 0 and binary.find('.') == 1 ): #print binary + "/t>>>/t" + "Error with dot./n" #return False #else: #for i in binary: #if i not in ['1','0','-','.']: #print binary + "/t>>>/t" + "Error, your number can only has /"1 0 - ./" symbols./n" #return False #检测极性 negative = 0 if binary[0] == '-': negative = 1 binary = binary[1:] integer = "" decimal = "" dot = binary.find('.') if dot == -1: integer = binary else: integer = binary[:dot] decimal = binary[dot+1:] cnt1=integer.__len__() cnt2=decimal.__len__() if cnt1 != 0: temp = 0 index_reverse = range(0,cnt1) for i in index_reverse: temp = temp + int(integer[i]) * ( 2 ** (cnt1 - i - 1) ) integer = temp else: integer = 0 if cnt2 != 0: temp = 0 index = range(1,cnt1+1) for i in index: temp = temp + int(decimal[ i-1 ]) * (2 ** (-1*i)) decimal = temp else: decimal = 0 result = integer + decimal if negative == 1: result = -1 * result return result ############################ Test Part###########################if __name__=="__main__": print "测试1-- mybin:/n" for i in [125, 1.3, 2.5, 0, -1, -5.4]: if mybin(i) != False: print str(i) + "/t==>/t" + mybin(i) + '/n' print "测试2-- mydev:/n" for i in ['-1001.1100', '-1101','111.111','0.1101','1001','0']: if mydec(i) != False: print i + "/t==>/t" + str(mydec(i)) + '/n' #print "测试3:/n" #for i in [ '123' ]: #if mybin(i) != False: #print str(i) + "/t==>/t" + mybin(i) + '/n' #print "测试4:/n" #for i in ['123', '101.1.1.0', '112-212', '-.23', '111.', '.10']: #if mydec(i) != False: #print i + "/t==>/t" + str(mydec(i)) + '/n'