What Is in the Rust Prelude and Why?

The Rust prelude is a set of standard library items automatically imported into every Rust program, so you don't need to write use statements for them. It includes common types like String, Vec, and Option, traits like Clone and Display, and functions like print! and println!.

// No 'use' needed; String, Vec, and println! are in the prelude
let greeting = String::from("Hello");
let numbers = vec![1, 2, 3];
println!("{}", greeting);

If you need something not in the prelude (like std::fs::read_to_string), you must import it explicitly with use.

The prelude is like a starter kit that comes with every new Rust program, containing the most commonly used tools so you don't have to ask for them every time. It saves you from typing repetitive import commands for basic things like text handling or lists. Think of it as the default toolbox you get when you start building, so you only need to fetch extra tools if you need something specialized.