How to convert hex values to floating point number in python

Question

I have hex value 4396 eccd. If I convert it to floating point number using some online calculator, I get value as 301.85 which is correct.

But when I convert it using python, I get some different value:

>>> float.fromhex('0x4396eccd')
1133964493.0

can anyone please help me on why its showing wrong value in python. Thanks

Abhay Salvi · Accepted Answer · 2020-03-20 08:04:45Z

2

Instead of using fromhex() for hex string to float number, you should better use struct module.

In python 2.x

>>> import struct
>>> struct.unpack('!f', '41973333'.decode('hex'))[0]
18.899999618530273

In python 3.x use:

bytes.fromhex('41973333') instead of '41973333'.decode('hex')

So it will be as follows:

>>> import struct
>>> struct.unpack('!f', bytes.fromhex('41973333'))[0]
18.899999618530273

answered Mar 20, 2020 at 6:50

Abhay Salvi

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7 Comments

Your solution gives me this error: AttributeError: 'str' object has no attribute 'decode'

Sorry my bad. Check it again.

For me it is working. Did it worked for you? If it worked then please do mark it as solved and if not then please let me know.

Thanks can you have a look at this question please stackoverflow.com/questions/60770615/…

I have answered that in a comment. @SAndrew

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