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Trait std::fmt::LowerExp

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.

Examples

Basic usage with f64:

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 = 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: {:e}", l),
    "l in scientific notation is: 1e2"
);

assert_eq!(
    format!("l in scientific notation is: {:05e}", l),
    "l in scientific notation is: 001e2"
);

Required methods

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

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Implementors

impl LowerExp for f32[src]

impl LowerExp for f64[src]

impl LowerExp for i8[src]

impl LowerExp for i16[src]

impl LowerExp for i32[src]

impl LowerExp for i64[src]

impl LowerExp for i128[src]

impl LowerExp for isize[src]

impl LowerExp for u8[src]

impl LowerExp for u16[src]

impl LowerExp for u32[src]

impl LowerExp for u64[src]

impl LowerExp for u128[src]

impl LowerExp for usize[src]

impl<'_, T> LowerExp for &'_ T where
    T: LowerExp + ?Sized, [src]

impl<'_, T> LowerExp for &'_ mut T where
    T: LowerExp + ?Sized, [src]

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© 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