# Trait alloc::fmt::LowerHex

1.0.0 · source · [−]

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

Expand description

`x` formatting.

The `LowerHex` trait should format its output as a number in hexadecimal, with `a` through `f` in lower case.

For primitive signed integers (`i8` to `i128`, and `isize`), negative values are formatted as the two’s complement representation.

The alternate flag, `#`, adds a `0x` in front of the output.

For more information on formatters, see the module-level documentation.

## Examples

Basic usage with `i32`:

    let x = 42; // 42 is '2a' in hex

    assert_eq!(format!("{x:x}"), "2a");
    assert_eq!(format!("{x:#x}"), "0x2a");

    assert_eq!(format!("{:x}", -16), "fffffff0");

Run

Implementing `LowerHex` on a type:

    use std::fmt;

    struct Length(i32);

    impl fmt::LowerHex for Length {
        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
            let val = self.0;

            fmt::LowerHex::fmt(&val, f) // delegate to i32's implementation
        }
    }

    let l = Length(9);

    assert_eq!(format!("l as hex is: {l:x}"), "l as hex is: 9");

    assert_eq!(format!("l as hex is: {l:#010x}"), "l as hex is: 0x00000009");

Run

## Required Methods

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

Formats the value using the given formatter.

## Implementors

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### impl LowerHex for i8

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### impl LowerHex for i16

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### impl LowerHex for i32

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### impl LowerHex for i64

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### impl LowerHex for i128

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### impl LowerHex for isize

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### impl LowerHex for u8

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### impl LowerHex for u16

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### impl LowerHex for u32

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### impl LowerHex for u64

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### impl LowerHex for u128

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### impl LowerHex for usize

1.34.0 · source

### impl LowerHex for NonZeroI8

1.34.0 · source

### impl LowerHex for NonZeroI16

1.34.0 · source

### impl LowerHex for NonZeroI32

1.34.0 · source

### impl LowerHex for NonZeroI64

1.34.0 · source

### impl LowerHex for NonZeroI128

1.34.0 · source

### impl LowerHex for NonZeroIsize

1.28.0 · source

### impl LowerHex for NonZeroU8

1.28.0 · source

### impl LowerHex for NonZeroU16

1.28.0 · source

### impl LowerHex for NonZeroU32

1.28.0 · source

### impl LowerHex for NonZeroU64

1.28.0 · source

### impl LowerHex for NonZeroU128

1.28.0 · source

### impl LowerHex for NonZeroUsize

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### impl<T> LowerHex for &Twhere
T: LowerHex + ?Sized,

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### impl<T> LowerHex for &mut Twhere
T: LowerHex + ?Sized,

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### impl<T> LowerHex for Saturating<T>where
T: LowerHex,

1.11.0 · source

### impl<T> LowerHex for Wrapping<T>where
T: LowerHex,

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### impl<T, const LANES: usize> LowerHex for Simd<T, LANES>where
LaneCount<LANES>: SupportedLaneCount,
T: SimdElement + LowerHex,