NumPy: Count the frequency of unique values in numpy array
NumPy: Array Object Exercise-94 with Solution
Write a NumPy program to count the frequency of unique values in numpy array.
import numpy as np a = np.array( [10,10,20,10,20,20,20,30, 30,50,40,40] ) print("Original array:") print(a) unique_elements, counts_elements = np.unique(a, return_counts=True) print("Frequency of unique values of the said array:") print(np.asarray((unique_elements, counts_elements)))
Original array: [10 10 20 10 20 20 20 30 30 50 40 40] Frequency of unique values of the said array: [[10 20 30 40 50] [ 3 4 2 2 1]]
Python Code Editor:
Have another way to solve this solution? Contribute your code (and comments) through Disqus.
What is the difficulty level of this exercise?
Test your Python skills with w3resource's quiz
Python: Tips of the Day
Getting the last element of a list:
some_list[-1] is the shortest and most Pythonic.
In fact, you can do much more with this syntax. The some_list[-n] syntax gets the nth-to-last element. So some_list[-1] gets the last element, some_list[-2] gets the second to last, etc, all the way down to some_list[-len(some_list)], which gives you the first element.
You can also set list elements in this way. For instance:
>>> some_list = [1, 2, 3] >>> some_list[-1] = 5 # Set the last element >>> some_list[-2] = 3 # Set the second to last element >>> some_list [1, 3, 5]
Note that getting a list item by index will raise an IndexError if the expected item doesn't exist. This means that some_list[-1] will raise an exception if some_list is empty, because an empty list can't have a last element.
- New Content published on w3resource:
- Scala Programming Exercises, Practice, Solution
- Python Itertools exercises
- Python Numpy exercises
- Python GeoPy Package exercises
- Python Pandas exercises
- Python nltk exercises
- Python BeautifulSoup exercises
- Form Template
- Composer - PHP Package Manager
- PHPUnit - PHP Testing
- Laravel - PHP Framework