Learning Rust: Strings and Immutables

A Quick Note About Strings (and Comparing Them)

When comparing a string literal to a String, use .trim() to remove the new line character from the String. For example, inside of a loop I want to continually ask the user for string until they enter "quit." The following code won't work:

println!("Give me a number: (enter 'quit' when all numbers entered)");

let mut n = String::new();

io::stdin().read_line(&mut n).expect("Failed to read line.");

if n == "quit" {
    break;
}

The String::new() adds a newline character to the end, so for that to be "quit" instead of "quit/n", it needs to be trimmed:

println!("Give me a number: (enter 'quit' when all numbers entered)");

let mut n = String::new();

io::stdin().read_line(&mut n).expect("Failed to read line.");

if n.trim() == "quit" {
    break;
}

Arrays and Vectors

Variables are immutable by default. Arrays' size are immutable. Vectors are what other programming languages would noramlly call an array (JS) or list (Python).