In [1]:

    

import struct
import binascii


    

In [2]:

    

f_max_s = '7fefffffffffffff'


    

In [3]:

    

print(binascii.unhexlify(f_max_s))


    

    




b'\x7f\xef\xff\xff\xff\xff\xff\xff'

In [4]:

    

print(type(binascii.unhexlify(f_max_s)))


    

    




<class 'bytes'>

In [5]:

    

print(struct.unpack('>d', binascii.unhexlify(f_max_s)))


    

    




(1.7976931348623157e+308,)

In [6]:

    

print(struct.unpack('>d', binascii.unhexlify(f_max_s))[0])


    

    




1.7976931348623157e+308

In [7]:

    

print(type(struct.unpack('>d', binascii.unhexlify(f_max_s))[0]))


    

    




<class 'float'>

In [8]:

    

def hex_to_double(s):
    if s.startswith('0x'):
        s = s[2:]
    s = s.replace(' ', '')
    return struct.unpack('>d', binascii.unhexlify(s))[0]


    

In [9]:

    

print(hex_to_double('7fefffffffffffff'))


    

    




1.7976931348623157e+308

In [10]:

    

print(hex_to_double('0x7fefffffffffffff'))


    

    




1.7976931348623157e+308

In [11]:

    

print(hex_to_double('0x7fef ffff ffff ffff'))


    

    




1.7976931348623157e+308

In [12]:

    

print(hex_to_double('0x4045 18f5 c28f 5c29'))


    

    




42.195

In [13]:

    

print(hex_to_double('7ff0000000000000'))


    

    




inf

In [14]:

    

print(hex_to_double('7ff0000000000001'))


    

    




nan

In [15]:

    

print(hex_to_double('0000000000000001'))


    

    




5e-324

In [16]:

    

# print(hex_to_double('ffff ffff ffff ffff ff'))
# error: unpack requires a buffer of 8 bytes


    

In [17]:

    

# print(hex_to_double('ffff ffff ffff ff'))
# error: unpack requires a buffer of 8 bytes


    

In [18]:

    

def hex_to_float(s):
    if s.startswith('0x'):
        s = s[2:]
    s = s.replace(' ', '')
    return struct.unpack('>f', binascii.unhexlify(s))[0]


    

In [19]:

    

print(hex_to_float('0x4228c7ae'))


    

    




42.19499969482422