RRust By Example
intermediateError Handling

Result Basic

Handle errors with Result<T, E> type.

Result Basic

Handle errors with Result type.

Difficulty

Intermediate

Code

rust
use std::num::ParseIntError;

fn parse_age(input: &str) -> Result<u32, ParseIntError> {
    input.parse::<u32>()
}

fn main() {
    match parse_age("25") {
        Ok(age) => println!("age: {}", age),
        Err(e) => println!("error: {}", e),
    }

    match parse_age("not a number") {
        Ok(age) => println!("age: {}", age),
        Err(e) => println!("error: {}", e),
    }
}

Explanation

Result represents success or failure.

Key Concepts

  • Read the code carefully and understand the data flow
  • Try modifying the example to see how it changes behavior
  • Run this code in the Rust Playground

Related Topics

Browse more examples in the error-handling category to build a complete understanding of this topic.

Common Compiler Errors in This Topic

Use these error pages as a debugging companion while practicing this example category.

E0308

mismatched types (expected, found)

Learn what Rust error E0308 means, why it happens, and how to fix it with practical code examples.

E0599

no method named found for type

Learn what Rust error E0599 means, why it happens, and how to fix it with practical code examples.

E0277

the trait bound is not satisfied

Learn what Rust error E0277 means, why it happens, and how to fix it with practical code examples.

More Error Handling Examples

Custom Error Type

Define custom error types with thiserror or manually.

Map and Transform Errors

Transform error types with map_err and and_then.

Option Basic

Handle optional values with Option<T>.

Question Mark Operator

Use ? to propagate errors concisely.