Trait LowerExp

pub trait LowerExp {
    // Required method
    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error> ;
}

core e formatting.

Re-exported from core::fmt:: .

---

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.

Errors

This function should return Err if, and only if, the provided Formatter returns Err. String formatting is considered an infallible operation; this function only returns a Result because writing to the underlying stream might fail and it must provide a way to propagate the fact that an error has occurred back up the stack.

Implementors

impl LowerExp for f32

impl LowerExp for f64

impl LowerExp for i8

impl LowerExp for i16

impl LowerExp for i32

impl LowerExp for i64

impl LowerExp for i128

impl LowerExp for isize

impl LowerExp for u8

impl LowerExp for u16

impl LowerExp for u32

impl LowerExp for u64

impl LowerExp for u128

impl LowerExp for usize

impl LowerExp for f32_be

impl LowerExp for f32_le

impl LowerExp for f64_be

impl LowerExp for f64_le

impl LowerExp for i16_be

impl LowerExp for i16_le

impl LowerExp for i32_be

impl LowerExp for i32_le

impl LowerExp for i64_be

impl LowerExp for i64_le

impl LowerExp for i128_be

impl LowerExp for i128_le

impl LowerExp for u16_be

impl LowerExp for u16_le

impl LowerExp for u32_be

impl LowerExp for u32_le

impl LowerExp for u64_be

impl LowerExp for u64_le

impl LowerExp for u128_be

impl LowerExp for u128_le

impl LowerExp for f32_ube

impl LowerExp for f32_ule

impl LowerExp for f64_ube

impl LowerExp for f64_ule

impl LowerExp for i16_ube

impl LowerExp for i16_ule

impl LowerExp for i32_ube

impl LowerExp for i32_ule

impl LowerExp for i64_ube

impl LowerExp for i64_ule

impl LowerExp for i128_ube

impl LowerExp for i128_ule

impl LowerExp for u16_ube

impl LowerExp for u16_ule

impl LowerExp for u32_ube

impl LowerExp for u32_ule

impl LowerExp for u64_ube

impl LowerExp for u64_ule

impl LowerExp for u128_ube

impl LowerExp for u128_ule

impl LowerExp for f32x4

impl LowerExp for f32x8

impl LowerExp for f64x2

impl LowerExp for f64x4

impl LowerExp for i8x16

impl LowerExp for i8x32

impl LowerExp for i16x8

impl LowerExp for i16x16

impl LowerExp for i32x4

impl LowerExp for i32x8

impl LowerExp for i64x2

impl LowerExp for i64x4

impl LowerExp for u8x16

impl LowerExp for u16x8

impl LowerExp for u16x16

impl LowerExp for u32x4

impl LowerExp for u32x8

impl LowerExp for u64x2

impl LowerExp for u64x4

impl LowerExp for ExampleBitfield

Available on crate feature _bit_u8 and doc only.

impl LowerExp for ExampleBitfieldCustom

Available on crate feature _bit_u8 and doc only.

impl LowerExp for ExampleBitfieldExtra

Available on crate feature _bit_u8 and doc only.

impl LowerExp for ExampleEnumSet

Available on doc only.

impl LowerExp for m128

impl LowerExp for m128d

impl LowerExp for m128i

impl LowerExp for m256

impl LowerExp for m256d

impl LowerExp for m256i

impl<'t, T, F, U> LowerExp for OptionFmtOrElse<'t, T, F>

where T: LowerExp, F: Fn() -> U, U: Display,

impl<'t, T, U> LowerExp for OptionFmtOr<'t, T, U>

where T: LowerExp, U: Display,

impl<T> LowerExp for &T

where T: LowerExp + ?Sized,

impl<T> LowerExp for &mut T

where T: LowerExp + ?Sized,

impl<T> LowerExp for NonZero<T>

where T: ZeroablePrimitive + LowerExp,

impl<T> LowerExp for OptionFmt<'_, T>

where T: LowerExp,

impl<T: LowerExp> LowerExp for Bitwise<T>

impl<T: LowerExp> LowerExp for Frac<T>

impl<T: LowerExp> LowerExp for Int<T>