Extract LSB bit from a Byte in python

Question

I have a byte in variable 'DATA'. I want to extract the LSB bit out of it and print it. I'm very new to python, I found many articles with complex bitwise addition logic and all which was very tough to understand. I'm looking for a simple logic like we do with the strings eg DATA[7:1] Please help me out...

score 20 · Accepted Answer · answered Jan 24 '14 at 19:59

20

Is your "byte" an int? If so, just take bitwise AND (&) with 1 (or, if you want to be more explicit, the binary literal 0b1) to get the least significant bit.

>>> x = 14
>>> x & 1
0
>>> x = 15
>>> x & 1
1

Is your "byte" a bytes object? If so, just index into it and take bitwise AND.

>>> y = bytes([14, 15])
>>> y[0] & 1
0
>>> y[1] & 1
1

answered Jan 24 '14 at 19:59

senshin

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@Nikhil When you read a file in binary mode (`rb`), you get a `bytes` object from `file.read()`. To find the least significant bit, take bitwise AND with `0b1`. Note that you will need to figure out which parts of the file are header and which parts are actual image data. It may help to use a library like PIL. – senshin Jan 24 '14 at 20:23

score 7 · Answer 2 · answered Mar 22 '20 at 00:02

Simplest and probably fastest:

least_significant_bit_of_x = x & -x

You can find more tricks here: https://www.informit.com/articles/article.aspx?p=1959565

Although the go-to reference for bitwise "black magic" is Knuth's "The Art of Computer Programming, vol. 1".

ASHISH R · Answer 3 · 2017-06-29T01:59:38.450

-2

Right shift by the number n and take the last bit by and 1

num >> n &1

edited Jun 29 '17 at 01:59

answered Jun 29 '17 at 01:23

ASHISH R

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Extract LSB bit from a Byte in python

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