Скачать или смотреть Handling Result Code Duplication in Rust match Bindings Idiomatically

Learn how to simplify Rust code that handles `Result` from binary search operations by avoiding duplication in match statements.
---
This video is based on the question https://stackoverflow.com/q/79477164/ asked by the user 'kesarling He-Him' ( https://stackoverflow.com/u/11930602/ ) and on the answer https://stackoverflow.com/a/79477176/ provided by the user 'JarroVGIT' ( https://stackoverflow.com/u/1557060/ ) 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: What is the idiomatic way to handle code duplication in match bindings for Result?

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 drop me a comment under this video.
---
Introduction

When working with Rust's binary_search_by_key method, you often end up with a Result that indicates whether the key was found (Ok) or not (Err). Typically, both arms of the match may return an index used for insertion or retrieval.

The Problem

The common pattern looks like this:

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

Here, you are returning idx in both cases, causing duplicated code that could be simplified.

Idiomatic Rust Solution

Rust provides the unwrap_or_else method on Result to handle the Err case concisely while returning the Ok value directly. Since both arms return the same type (usize), you can write:

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

Explanation:

binary_search_by_key returns Result<usize, usize>.

unwrap_or_else unwraps the Ok value if found.

If it’s Err, it applies the closure, here just returning the Err index.

This avoids the verbose match statement and makes your code cleaner and easier to maintain.

Summary

Use unwrap_or_else on the Result from binary_search_by_key to extract the index regardless of whether the key was found.

This approach eliminates duplicated idx returns in match arms.

It leverages Rust’s expressive standard library to write concise, idiomatic code.

Example

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

This pattern ensures you always get the correct insertion index.



By leveraging unwrap_or_else, you simplify handling Result matches when both arms yield the same type, improving code clarity and safety.