Скачать или смотреть How to Calculate the Sum of Overlapping Values in a Kotlin ArrayList

Discover how to efficiently compute the total sum of overlapping values in a Kotlin `ArrayList`, particularly for items like fruits. Learn step-by-step techniques involving filtering and summing.
---
This video is based on the question https://stackoverflow.com/q/65503822/ asked by the user '우주산' ( https://stackoverflow.com/u/14904561/ ) and on the answer https://stackoverflow.com/a/65510547/ provided by the user 'Tenfour04' ( https://stackoverflow.com/u/506796/ ) 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: Kotlin ArrayList overlapping value plus?

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.
---
How to Calculate the Sum of Overlapping Values in a Kotlin ArrayList

Managing data in an ArrayList is a common task for Kotlin developers, especially when handling similar or overlapping data points. If you find yourself needing to calculate the total sum of overlapping values, for example, with products like Apple and Banana, this guide will guide you through a practical solution using Kotlin’s powerful collection functions.

The Problem at Hand

Let’s take a closer look at a scenario where you have a list of products with their respective values, but the same product appears multiple times with different values. Here's an example of the data you might have:

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

Your goal is to compute the total values for each fruit. For instance, you want to sum all values related to Apple, which are 3,000, 3,100, and 3,200. To achieve this, you can leverage Kotlin's collection functions effectively.

The Solution: Summing Overlapping Values

Step 1: Defining the Data Class

First, it is important to have a clean structure to represent your data. You've already defined a class called Statement_data. Here’s a quick reminder of what it looks like:

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

Step 2: Create Your List

Next, you’ll declare an ArrayList to hold your Statement_data objects. You will populate this list with your values:

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

Step 3: Filtering and Summing Values

To compute the total for a specific item, such as Apple, you can utilize Kotlin’s filter and sumBy functions. Here’s the robust code snippet that accomplishes this:

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

asSequence(): This method is used to convert the list to a sequence. Using a sequence allows for more efficient memory usage by skipping the copying of data as it filters through the list.

filter: This function filters the list based on the predicate you specify—in this case, we are interested in items where name is Apple.

sumBy: This method computes the sum of integers yielded by the provided selector function, which we specify as the value property.

Example Output

After running the above code, the variable numApples will contain the total sum of all Apple values:

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

Conclusion

This step-by-step method allows you to effortlessly calculate the sum of overlapping values in a Kotlin ArrayList. By leveraging Kotlin’s collection functions, you can efficiently filter and compute totals without much hassle. Whether you're dealing with fruits like Apple and Banana, or any other repeated entries, this approach will help streamline your data management tasks.

Feel free to adjust the filtering criteria based on your requirements to sum up different products as needed. Happy coding!