有没有办法在python中查看float的内部表示？

Question

在python浮点教程中,

在碱2中,1/10是无限重复的部分

0.0001100110011001100110011001100110011001100110011 ...

如何让python解释器打印这种内心表示？repr(0.1)没有帮助.

Answer 1

您可以使用struct模块获取float的内部表示.获得表示后,您只需将字符转换为序数值并将其格式化为二进制.

>>> import struct
>>> def float_rep(num):
    return ''.join("{:08b}".format(ord(elem)) for elem in struct.pack('!f', num))

>>> float_rep(0.1)
'00111101110011001100110011001101'

编辑

虽然上面会为你提供内部的实际表示,但我想,你对二进制的二进制当量更感兴趣.以下内容足以满足您的查询需求

>>> def float_to_bin(num):
    sign = '-' if  num < 0 else ''
    num = abs(num)
    whole = int(num)
    num  -= whole
    yield sign + bin(whole) + '.'
    while num:
        num*= 2
        whole = int(num)
        yield str(whole)
        num -= whole


>>> ''.join(islice(float_to_bin(1.1),None,20))
'1.0001100110011001100'
>>> ''.join(islice(float_to_bin(-1.1),None,20))
'-1.0001100110011001100'
>>> ''.join(islice(float_to_bin(.1),None,20))
'0.0001100110011001100'
>>> ''.join(islice(float_to_bin(0),None,20))
'0.'
>>> ''.join(islice(float_to_bin(1),None,20))
'1.'
>>> ''.join(islice(float_to_bin(0.25),None,20))
'0.01'
>>> ''.join(islice(float_to_bin(0.5),None,20))
'0.1'
>>> ''.join(islice(float_to_bin(-0.5),None,20))
'-0.1'