MATLAB Answers

Hex to float like python struct.unpack()

21 views (last 30 days)
I'm trying to convert a hex string to a float in the same manner python function struct.unpack(), , which is using the IEEE754 binary32 0r 64 depending on foat or double.
As an example I have
hex = 'C956F53D'
When i run it in a struct.unpack() i get the value:
data = 0.1198
And this is correct. However, when i try the following matlab function i get something totally different.
>> hex2dec(hex)
ans =
>> typecast(uint32(hex2dec(hex)),'single')
ans =
Does anybody know the difference or what I'm doing wrong?


Sign in to comment.

Accepted Answer

Ameer Hamza
Ameer Hamza on 16 Sep 2020
This is the correct way
hex = 'C956F53D';
x = hex2dec(reshape(hex, 2, []).');
dec = typecast(uint8(x), 'single')


Sebastian Thuné
Sebastian Thuné on 16 Sep 2020
You my friend are a superstar! Thanks!
So i basically have to put the bytes in an array first. Why is that? Is it because typecast has to go byte by byte?
Ameer Hamza
Ameer Hamza on 16 Sep 2020
Yes, you need to convert it into an uint8 array. Then MATLAB reads the bytes from the input array and converts those bytes into 'single'. It is pretty similar to pointer typecasting in C.
I am glad to be of help!

Sign in to comment.

More Answers (1)

James Tursa
James Tursa on 16 Sep 2020
Could be a Big Endian vs Little Endian thing. E.g., inserting a swapbytes( ) step:
>> hex = 'C956F53D'
hex =
>> typecast(swapbytes(uint32(hex2dec(hex))),'single')
ans =


Sign in to comment.

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!