&str introduces a string slice, which is an immutable reference to UTF-8 encoded string data stored in a block of memory. String literals (”Hello”), are stored in the program’s binary.

Rust’s String type is a wrapper around a vector of bytes. As with a Vec<T>, it is owned.

As with many other types String::from() creates a string from a string literal; String::new() creates a new empty string, to which string data can be added using the push() and push_str() methods.

The format!() macro is a convenient way to generate an owned string from dynamic values. It accepts the same format specification as println!().

You can borrow &str slices from String via & and optionally range selection. If you select a byte range that is not aligned to character boundaries, the expression will panic. The chars iterator iterates over characters and is preferred over trying to get character boundaries right.

For C++ programmers: think of &str as std::string_view from C++, but the one that always points to a valid string in memory. Rust String is a rough equivalent of std::string from C++ (main difference: it can only contain UTF-8 encoded bytes and will never use a small-string optimization).

Byte strings literals allow you to create a &[u8] value directly:

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