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Counting With Python's Counter (Summary)

Christopher Trudeau
Counting With Python's Counter Christopher Trudeau 01:20
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When you need to count several repeated objects in Python, you can use Counter from collections. This class provides an efficient and Pythonic way to count things without the need for using traditional techniques involving loops and nested data structures. This can make your code cleaner and faster.

In this video course, you learned how to:

  • Count several repeated objects using different Python tools
  • Create quick and efficient counters with Python’s Counter
  • Retrieve the most common objects in a particular counter
  • Update and manipulate object counts
  • Use Counter to facilitate further computations
  • Implement Counter instances as multisets

For more information on concepts covered in this course, you can check out:

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Course Slides (.pdf)

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00:00 In the previous lesson, I showed you how to use the Counter class as a multiset. In this lesson, I’ll summarize the course. In this course, I showed you all about counting problems and how to use Python’s Counter class to help you solve those kinds of problems.

00:16 Remember that you can initialize the counter with sequences, dictionaries, and arguments, as well as other Counter classes. Once you’ve initialized the counter, you can get the most frequent items in the class by calling the .most_common() method. You can also get the contents using .keys(), .values(), .items(), and .elements().

00:41 In this course, I covered several different practical applications of the Counter class, including counting letter frequency, building histograms, determining the statistical mode, counting file types, and building shopping carts.

00:57 And finally, I went a little math geek and described multisets and their operations and how you can use a counter to implement them.

01:07 That’s all I have on counters. Thanks for your attention. I hope you enjoyed the course. Pause for one Mississippi, two Mississippi, three Mississippi, and fade to black.

James on March 10, 2022

Nicely done. Examples are good.

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