Questions
Rust questions
Choose a question page, learn the concept, then test your understanding with a quiz.
Absolute Values in Rust: Using the abs() Method
Learn how to calculate absolute values in modern Rust with abs(), handle signed integer overflow, and choose safer alternatives.
Accepting Iterators in Rust Functions with impl Iterator
Learn how to write Rust functions that accept HashMap iterators using generic bounds or impl Iterator, avoiding trait object and lifetime errors.
Access Enum Variant Values in Rust with Pattern Matching
Learn how to extract and print values stored in Rust enum variants using match and if let pattern matching, with practical examples.
Accessing Cargo Package Metadata in Rust
Learn how to read Cargo package metadata like version, name, and authors in Rust using compile-time environment macros.
Associated Types vs Generic Type Parameters in Rust: When to Use Each
Learn when to use associated types vs generic parameters in Rust traits, with clear rules, examples, and practical API design advice.
Automatically Recompile Rust Files with Cargo Watch
Learn how Cargo rebuilds changed Rust code and how cargo-watch automatically runs cargo check, build, test, or run when files change.
Binary-Only Dependencies in Rust Cargo
Learn how to keep Rust library dependencies light by using optional Cargo dependencies, features, required-features, or separate packages.
Can a Struct Extend Another Struct in Rust? Composition vs Inheritance
Learn how Rust handles struct reuse without inheritance, using composition, traits, and wrapper structs with practical examples.
Check Whether a String Contains a Substring in Rust
Learn how to check whether a Rust string contains a substring using str::contains, with examples, pitfalls, and practical patterns.
Check Whether a Vec Contains a Value in Rust
Learn how to check whether a Rust Vec contains a value using contains and iterator methods, with examples, pitfalls, and practical patterns.
Clone a Vector in a Generic Rust Function
Learn the idiomatic Rust way to clone a slice or vector in a generic function, mutate the copy, and return a new owned Vec<T>.
Compare Rust Enums Without Verbose Pattern Matching
Learn how to compare Rust enum variants with PartialEq and matches!, including iterator filters, borrowed values, and common pitfalls.
Concise HashMap Initialization in Rust
Learn concise, declarative ways to initialize Rust HashMaps using arrays, iterators, collect, HashMap::from, and counting patterns.
Convert &str to &[u8] in Rust
Learn how to convert a Rust &str into a &[u8] with as_bytes(), why the types differ, and how UTF-8 affects byte slices.
Convert C Strings to Rust Strings and Back with Rust FFI
Learn to safely convert null-terminated C strings to Rust strings and create C strings for Rust FFI using CStr and CString.
Convert Option<String> to Option<&str> in Rust
Learn the idiomatic Rust way to convert Option<String> into Option<&str> using as_deref, as_ref, and unwrap_or without extra allocation.
Convert PathBuf to String in Rust Safely
Learn how to convert PathBuf to String in Rust, when conversion can fail, and safer alternatives for paths and file APIs.
Convert Result to Option in Rust with ok()
Learn how to convert Rust Result values into Option with ok(), use filter_map for parsing, and choose when errors should be ignored or handled.
Convert a Rust Enum to a User-Facing String
Learn how to convert Rust enum variants into user-facing strings with Display, string-returning methods, and practical formatting patterns.
Convert a String to a Vector of Bytes in Rust
Learn how to convert Rust strings into Vec<u8> with as_bytes, to_vec, and into_bytes, including UTF-8 behavior and ownership rules.
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