CODEWITHSUNDEEP
pythonarduinointbyte
Grum
Grum

Reputation: 318

How to transform a byte value "b'27 '" into int 27

How to get the number in a byte variable ?

I have to transfer data from Arduino to Raspberry Pi with serial and python. I succeed to isolate the variable but its type is bytes, how to get this into an int variable ?

The variable is 

b'27'

but i want to get

27

I tried

print(int.from_bytes(b'\x27', "big", signed=True))

But i don't succeed to get the correct number 27

Upvotes: 0

Views: 421

Answers (2)

HFBrowning
HFBrowning

Reputation: 2336

To supplement the helpful and practical answer given by C.Nivs, I would like to add that if you had wanted to use int.from_bytes() to retrieve the value 27, you would have needed to do:

int.from_bytes(b'\x1B', "big", signed=True)

because '\x27' is actually the hex value for the value 39. There are loads of conversion tables online that can be helpful for cross-referencing decimal against hex values. These two forms are only 1:1 for values less than 10.

Upvotes: 1

C.Nivs
C.Nivs

Reputation: 13126

You can use decode to get it to a regular str and then use int:

x = b'27'

y = int(x.decode()) # decode is a method on the bytes class that returns a string
type(y)
# <class 'int'>

Alternatively:

y = int(b'27')
type(y)
# <class 'int'>

Per @chepner's comment, you'll want to note cases where weird encoding can break the latter approach, and for non-utf-8 encoding it could break both

Upvotes: 4

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