CODEWITHSUNDEEP
python-3.x
lordhog
lordhog

Reputation: 3707

In Python, convert an array of bytes to integer

I am retrieving bytes of data from an IC2 device using the read_i2c_block_data function. Within this block of data are signed 16-bit values that I want to display. I am able to print out the value correctly using the following:

print ("PC12  : %d mW" % int.from_bytes((return_data[5],return_data[6]), byteorder='little', signed=True))

Though, I have been trying print out the value using the following, which doesn't work and I don't know why. I am curious to why I can't get it to work.

print ("PC12  : %d mW" % int.from_bytes(return_data[5:6], byteorder='little', signed=True))

Does anyone know what I am doing wrong? I thought I could specify the range in the from_bytes function.

Thanks, Mark

Upvotes: 1

Views: 692

Answers (1)

vitaut
vitaut

Reputation: 55524

return_data[5:6] returns an array consisting of a single element at index 5:

>>> return_data = b'\00\01\02\03\04\05\06'
>>> return_data[5:6]
b'\x05'

Since you want to convert a 16-bit integer, you need to use return_data[5:7].

Upvotes: 2

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