pub trait LowerExp {
fn fmt(&self, f: &mut Formatter) -> Result<(), Error>;
}
e formatting.
The LowerExp trait should format its output in scientific notation with a lower-case e.
For more information on formatters, see the module-level documentation.
Basic usage with i32:
let x = 42.0; // 42.0 is '4.2e1' in scientific notation
assert_eq!(format!("{:e}", x), "4.2e1"); Implementing LowerExp on a type:
use std::fmt;
struct Length(i32);
impl fmt::LowerExp for Length {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
let val = self.0;
write!(f, "{}e1", val / 10)
}
}
let l = Length(100);
println!("l in scientific notation is: {:e}", l); impl<'a, T> LowerExp for &'a mut T where
T: LowerExp + ?Sized,
impl<'a, T> LowerExp for &'a T where
T: LowerExp + ?Sized,
impl LowerExp for f32
impl LowerExp for f64
© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/fmt/trait.LowerExp.html