How to use Sequence of Keys In NumPy
Sorting a array using a sequence of keys allows us to sort an array based on multiple criteria.
You can use this method with np.lexsort() function. The lexsort() function returns an array of indices that would sort the original array.
Example
Get stable sort using a sequence of keys.
Python3
import numpy as np # Numpy array created # First column a = np.array([9, 3, 1, 3, 4, 3, 6]) # Second column b = np.array([4, 6, 9, 2, 1, 8, 7]) print('column a, column b') for (i, j) in zip(a, b): print(i, ' ', j) # Sort by a then by b ind = np.lexsort((b, a)) print('Sorted indices->', ind) |
Output:
column a, column b
9 4
3 6
1 9
3 2
4 1
3 8
6 7
Sorted indices-> [2 3 1 5 4 6 0]
Also Check: Sorting, Searching and Counting in NumPy
NumPy Array Sorting | How to sort NumPy Array
Sorting an array is a very important step in data analysis as it helps in ordering data, and makes it easier to search and clean.
In this tutorial, we will learn how to sort an array in NumPy. You can sort an array in NumPy:
- Using np.sort() function
- in-line sort
- sorting along different axes
- Using np.argsort() function
- Using np.lexsort() function