What is the simplest way to convert a string to upper case in Rust?

If you use the std::string::String type instead of &str, there is a less verbose way with the additional benefit of Unicode support: fn main() { let test_str = “übercode”; // type &str let uppercase_test_string = test_str.to_uppercase(); // type String let uppercase_test_str = uppercase_test_string.as_str(); // back to type &str println!{“{}”, test_str}; println!{“{}”, uppercase_test_string}; println!{“{}”, uppercase_test_str}; }