Mastering Rust - Second Edition

Borrowed strings – &str

We can also have strings as references called string slices. These are denoted by &str (pronounced as stir), which is a reference to a str type. In constrast to the String type, str is a built-in type known to the compiler and is not something from the standard library. String slices are created as &str by default—a pointer to a UTF-8 encoded byte sequence. We cannot create and use values of the bare str type, as it represents a contiguous sequence of UTF-8 encoded bytes with a finite but unknown size. They are technically called unsized types. We'll explain unsized types later in this chapter.

str can only be created as a reference type. Let's assume we try to create a str type forcibly by providing the type signature ...