Скачать или смотреть Counting Occurrences in Nested Lists: Python Solutions

Achieve accurate comparisons and count occurrences in a 4D list against a 3D reference in Python. Solve common coding problems with practical examples.
---
This video is based on the question https://stackoverflow.com/q/63037775/ asked by the user 'Carlos Eduardo Corpus' ( https://stackoverflow.com/u/12954626/ ) and on the answer https://stackoverflow.com/a/63039934/ provided by the user 'Prem Anand' ( https://stackoverflow.com/u/2614637/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Counting the number of occurrences and compare to another list

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Counting Occurrences in Nested Lists: Python Solutions

When working with complex data structures in Python, particularly lists of lists (or even more deeply nested lists), it’s common to encounter challenges when trying to count occurrences of certain elements and compare them against a reference list. In this guide, we will explore how to successfully count the occurrences in a 4D list and compare them to a 3D reference list using Python.

The Problem

A user was faced with the task of counting the numbers of occurrences within a 4D list and comparing those counts against a 3D reference list. Although they successfully computed the occurrences, they encountered issues during the comparison stage. The goal was to accurately reflect the occurrences in the first list of counters against the first 3D reference structure and the second list against the same reference.

Understanding the Data Structure

To break down the problem, let’s review the structures involved:

Reference List (3D): A list that contains sublists which reference pairs of numbers.

[[See Video to Reveal this Text or Code Snippet]]

Coordinates List (4D): A structure where occurrences of pairs will be counted.

[[See Video to Reveal this Text or Code Snippet]]

Occurrences: Using the Counter from the collections module, a list of counts for pairs of numbers is created.

The Counting Process

The initial steps include counting the occurrences of pairs within the 4D list:

[[See Video to Reveal this Text or Code Snippet]]

This generates a list of Counter objects that represent how many times each tuple appears in the original data.

The Comparison Process

In the code provided, the user aimed to compare the occurrences against the reference list but faced a discrepancy during the comparison, particularly with a specific count.

The Correct Way to Compare

The solution involves accurately navigating through each list of counters in occurrences and referencing the appropriate frequencies:

[[See Video to Reveal this Text or Code Snippet]]

Breaking Down the Solution

Iterate over occurrences: For each list of Counter objects generated from the occurrences.

Enumerate over reference: For each reference inside the respective nested structure of the reference list.

Access the tuple counts: Using the tuple to retrieve counts from the Counter.

Result

By implementing the above comparison structure, you will obtain results that align with expectations. The final output would look like this:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Navigating the intricacies of nested lists and their counts in Python can initially pose challenges. By effectively using the Counter class from the collections module and employing careful iteration and enumeration techniques, one can accurately compare lists and retrieve meaningful results.

Feel free to apply the steps outlined here to count occurrences and perform comparisons in your data work! Happy coding!