Trait std::fmt::LowerExp
pub trait LowerExp {
// Required method
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.
Examples
Basic usage with f64:
let x = 42.0; // 42.0 is '4.2e1' in scientific notation
assert_eq!(format!("{x:e}"), "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 = f64::from(self.0);
fmt::LowerExp::fmt(&val, f) // delegate to f64's implementation
}
}
let l = Length(100);
assert_eq!(
format!("l in scientific notation is: {l:e}"),
"l in scientific notation is: 1e2"
);
assert_eq!(
format!("l in scientific notation is: {l:05e}"),
"l in scientific notation is: 001e2"
);Required Methods
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>Formats the value using the given formatter.
Implementors
impl LowerExp for f32impl LowerExp for f64impl LowerExp for i8impl LowerExp for i16impl LowerExp for i32impl LowerExp for i64impl LowerExp for i128impl LowerExp for isizeimpl LowerExp for u8impl LowerExp for u16impl LowerExp for u32impl LowerExp for u64impl LowerExp for u128impl LowerExp for usizeimpl<T> LowerExp for &T
where
T: LowerExp + ?Sized,impl<T> LowerExp for &mut T
where
T: LowerExp + ?Sized,© 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