Rust really loves underscores😀

1 
fn main() {
    let tup = (500, 6.4, 1);
    let (_x, _y, _z) = tup;

    println!("The value of y is: {}", _y);  
}

if (_x, _y, _z) changes to (x, y, z),the compiler would say:

warning: unused variable: `y`
 --> src\main.rs:3:13
  |
3 |     let (x, y, z) = tup;
  |             ^ help: if this is intentional, prefix it with an underscore: `_y`
1 Like
2

It would point out you didn't use x and z, but you did use y so it wouldn't point that one out.

It's letting you know you probably have a logical error in your code (though you may see such warnings a lot while checking or compiling partially completed functions or the like). You can add underscores to silence the errors... but you could also make use of the variables, or remove them entirely if you don't need them.

1 Like
3

thx~

4

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