Python Slicing | Extract ‘k’ bits from a given position
How to extract ‘k’ bits from a given position ‘p’ in a number?
Input : number = 171 k = 5 p = 2 Output : The extracted number is 21 171 is represented as 10101011 in binary, so, you should get only 10101 i.e. 21. Input : number = 72 k = 5 p = 1 Output : The extracted number is 8 72 is represented as 1001000 in binary, so, you should get only 01000 i.e 8.
We have existing solution for this problem please refer Extract ‘k’ bits from a given position in a number link. We can solve this problem quickly in python using slicing. Approach is simple,
- Convert given number into it’s binary using bin() function and remove first two characters ‘0b’ from it, because bin function appends ‘0b’ as prefix in output binary string.
- We need to start extracting k bits from starting position p from right, that means end index of extracted sub-string will be end = (len(binary) – p) and start index will be start = end – k + 1 of original binary string.
- Convert extracted sub-string into decimal again.