Mastering Java Streams: How to Retrieve an Element's Name as a String

Discover how to efficiently use Java Streams to extract file names and compute rates, resulting in a cleaner and more functional code.
---
This video is based on the question https://stackoverflow.com/q/73844436/ asked by the user 'santa_cloudy' ( https://stackoverflow.com/u/19832072/ ) and on the answer https://stackoverflow.com/a/73844844/ provided by the user 'Arvind Kumar Avinash' ( https://stackoverflow.com/u/10819573/ ) 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: How to get an element's name as a String inside a stream in Java?

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

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Mastering Java Streams: How to Retrieve an Element's Name as a String

Java Streams are a powerful feature of the language that allow you to manipulate and process collections of data more effectively. In this guide, we're going to address a common problem that many developers encounter: how to access and use a list of file names within a stream to fetch associated rates based on the dates contained in those file names.

The Problem Statement

Imagine you have a list of file names representing dates, specifically in the format [1999-01-01, 1999-06-01, 1999-11-01]. You want to process this list in order to retrieve rates corresponding to those dates using a method called getRateAtDate. Your objective is to generate output in a formatted manner that specifies each date alongside its corresponding rate, like this:

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

The Solution

To achieve the objective, we can leverage Java Streams for cleaner and more readable code. Let’s break this down into manageable steps.

Step 1: Obtain the List of Dates

First, ensure you have a method getRatesFiles() that returns the list of file names as strings. The structure of your data should look something like this:

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

Step 2: Stream the List

Next, you will want to process this list using streams to filter and sort the file names. The first part of your stream should filter the files based on the given year (e.g., only files starting with "1999"):

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

Step 3: Map the Stream to Desired Output

Rather than using map twice (which can clutter the code), you can condense your stream logic into a single mapping operation that combines the date and the rate retrieval:

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

Step 4: Collect the Results

To get your results as a list or a single formatted String, you can use collect() to gather the results. If you want to join them into a single formatted string separated by new lines, here's how:

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

Putting It All Together

Here’s how the complete method will look:

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

Conclusion

By utilizing Java Streams, you not only streamline your code but also enhance its readability and efficiency. The method above effectively retrieves and formats the rates associated with given file names. Now you can easily adapt this approach to suit other similar scenarios in your coding projects.

With these steps, you're well on your way to mastering the use of streams in Java for data processing. Happy coding!

Видео Mastering Java Streams: How to Retrieve an Element's Name as a String канала vlogize