# Python Slicing | Extract ‘k’ bits from a given position

How to extract ‘k’ bits from a given position ‘p’ in a number?

**Examples:**

Input :number = 171 k = 5 p = 2Output :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 = 1Output :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.

`# Function to extract ‘k’ bits from a given ` `# position in a number ` ` ` `def` `extractKBits(num,k,p): ` ` ` ` ` `# convert number into binary first ` ` ` `binary ` `=` `bin` `(num) ` ` ` ` ` `# remove first two characters ` ` ` `binary ` `=` `binary[` `2` `:] ` ` ` ` ` `end ` `=` `len` `(binary) ` `-` `p ` ` ` `start ` `=` `end ` `-` `k ` `+` `1` ` ` ` ` `# extract k bit sub-string ` ` ` `kBitSubStr ` `=` `binary[start : end` `+` `1` `] ` ` ` ` ` `# convert extracted sub-string into decimal again ` ` ` `print` `(` `int` `(kBitSubStr,` `2` `)) ` ` ` `# Driver program ` `if` `__name__ ` `=` `=` `"__main__"` `: ` ` ` `num ` `=` `171` ` ` `k ` `=` `5` ` ` `p ` `=` `2` ` ` `extractKBits(num,k,p) ` ` ` ` ` |

*chevron_right*

*filter_none*

**Output:**

21

Don’t stop now and take your learning to the next level. Learn all the important concepts of Data Structures and Algorithms with the help of the most trusted course: DSA Self Paced. Become industry ready at a student-friendly price.

## Recommended Posts:

- Extract 'k' bits from a given position in a number.
- Python | K elements Slicing
- String Slicing in Python
- Python List Comprehension and Slicing
- Python | Reverse Slicing of given string
- Python | Variable list slicing
- Python | Custom slicing in List
- Python | Custom List slicing Sum
- Slicing range() function in Python
- Python | Reverse Incremental String Slicing
- Python | Reverse Interval Slicing String
- Python | Get the substring from given string using list slicing
- Interesting facts about strings in Python | Set 2 (Slicing)
- Python | Alternate range slicing in list
- Python Slicing | Reverse an array in groups of given size
- Basic Slicing and Advanced Indexing in NumPy Python
- Program to cyclically rotate an array by one in Python | List Slicing
- Python | Extract suffix after K
- numpy.extract() in Python
- Python | Extract characters except of K string

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.