# UniformInt in rand::distributions::uniform - Rust
The back-end implementing [`UniformSampler`] for integer types.
Keywords: rust, rustlang, rust-lang, UniformInt

# Struct rand::distributions::uniform::UniformInt

source · [−]

    pub struct UniformInt<X> { /* private fields */ }

Expand description

The back-end implementing `UniformSampler` for integer types.

Unless you are implementing `UniformSampler` for your own type, this type should not be used directly, use `Uniform` instead.

## Implementation notes

For simplicity, we use the same generic struct `UniformInt<X>` for all integer types `X`. This gives us only one field type, `X`; to store unsigned values of this size, we take use the fact that these conversions are no-ops.

For a closed range, the number of possible numbers we should generate is `range = (high - low + 1)`. To avoid bias, we must ensure that the size of our sample space, `zone`, is a multiple of `range`; other values must be rejected (by replacing with a new random sample).

As a special case, we use `range = 0` to represent the full range of the result type (i.e. for `new_inclusive($ty::MIN, $ty::MAX)`).

The optimum `zone` is the largest product of `range` which fits in our (unsigned) target type. We calculate this by calculating how many numbers we must reject: `reject = (MAX + 1) % range = (MAX - range + 1) % range`. Any (large) product of `range` will suffice, thus in `sample_single` we multiply by a power of 2 via bit-shifting (faster but may cause more rejections).

The smallest integer PRNGs generate is `u32`. For 8- and 16-bit outputs we use `u32` for our `zone` and samples (because it’s not slower and because it reduces the chance of having to reject a sample). In this case we cannot store `zone` in the target type since it is too large, however we know `ints_to_reject < range <= $unsigned::MAX`.

An alternative to using a modulus is widening multiply: After a widening multiply by `range`, the result is in the high word. Then comparing the low word against `zone` makes sure our distribution is uniform.

## Trait Implementations

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### impl<X: Clone> Clone for UniformInt<X>

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#### fn clone(&self) -> UniformInt<X>

Returns a copy of the value. Read more

1.0.0 · source

#### fn clone_from(&mut self, source: &Self)

Performs copy-assignment from `source`. Read more

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### impl<X: Debug> Debug for UniformInt<X>

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

Formats the value using the given formatter. Read more

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### impl<X: PartialEq> PartialEq<UniformInt<X>> for UniformInt<X>

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#### fn eq(&self, other: &UniformInt<X>) -> bool

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

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#### fn ne(&self, other: &UniformInt<X>) -> bool

This method tests for `!=`.

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### impl UniformSampler for UniformInt<i8>

#### type X = i8

The type sampled by this implementation.

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#### fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

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#### fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive bounds `[low, high]`. Read more

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#### fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X

Sample a value.

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#### fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn sample_single_inclusive<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and inclusive upper bound `[low, high]`. Read more

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### impl UniformSampler for UniformInt<i16>

#### type X = i16

The type sampled by this implementation.

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#### fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

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#### fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive bounds `[low, high]`. Read more

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#### fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X

Sample a value.

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#### fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn sample_single_inclusive<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and inclusive upper bound `[low, high]`. Read more

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### impl UniformSampler for UniformInt<usize>

#### type X = usize

The type sampled by this implementation.

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#### fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

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#### fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive bounds `[low, high]`. Read more

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#### fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X

Sample a value.

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#### fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn sample_single_inclusive<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and inclusive upper bound `[low, high]`. Read more

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### impl UniformSampler for UniformInt<u128>

#### type X = u128

The type sampled by this implementation.

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#### fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

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#### fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive bounds `[low, high]`. Read more

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#### fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X

Sample a value.

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#### fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn sample_single_inclusive<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and inclusive upper bound `[low, high]`. Read more

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### impl UniformSampler for UniformInt<i32>

#### type X = i32

The type sampled by this implementation.

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#### fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive bounds `[low, high]`. Read more

source

#### fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X

Sample a value.

source

#### fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn sample_single_inclusive<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and inclusive upper bound `[low, high]`. Read more

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### impl UniformSampler for UniformInt<i64>

#### type X = i64

The type sampled by this implementation.

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#### fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive bounds `[low, high]`. Read more

source

#### fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X

Sample a value.

source

#### fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn sample_single_inclusive<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and inclusive upper bound `[low, high]`. Read more

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### impl UniformSampler for UniformInt<i128>

#### type X = i128

The type sampled by this implementation.

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#### fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive bounds `[low, high]`. Read more

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#### fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X

Sample a value.

source

#### fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn sample_single_inclusive<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and inclusive upper bound `[low, high]`. Read more

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### impl UniformSampler for UniformInt<isize>

#### type X = isize

The type sampled by this implementation.

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#### fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive bounds `[low, high]`. Read more

source

#### fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X

Sample a value.

source

#### fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn sample_single_inclusive<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and inclusive upper bound `[low, high]`. Read more

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### impl UniformSampler for UniformInt<u8>

#### type X = u8

The type sampled by this implementation.

source

#### fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive bounds `[low, high]`. Read more

source

#### fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X

Sample a value.

source

#### fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn sample_single_inclusive<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and inclusive upper bound `[low, high]`. Read more

source

### impl UniformSampler for UniformInt<u16>

#### type X = u16

The type sampled by this implementation.

source

#### fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive bounds `[low, high]`. Read more

source

#### fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X

Sample a value.

source

#### fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn sample_single_inclusive<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and inclusive upper bound `[low, high]`. Read more

source

### impl UniformSampler for UniformInt<u32>

#### type X = u32

The type sampled by this implementation.

source

#### fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive bounds `[low, high]`. Read more

source

#### fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X

Sample a value.

source

#### fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn sample_single_inclusive<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and inclusive upper bound `[low, high]`. Read more

source

### impl UniformSampler for UniformInt<u64>

#### type X = u64

The type sampled by this implementation.

source

#### fn new<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn new_inclusive<B1, B2>(low_b: B1, high_b: B2) -> Self where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Construct self, with inclusive bounds `[low, high]`. Read more

source

#### fn sample<R: Rng + ?Sized>(&self, rng: &mut R) -> Self::X

Sample a value.

source

#### fn sample_single<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and exclusive upper bound `[low, high)`. Read more

source

#### fn sample_single_inclusive<R: Rng + ?Sized, B1, B2>(
low_b: B1,
high_b: B2,
rng: &mut R
) -> Self::X where
B1: SampleBorrow<Self::X> + Sized,
B2: SampleBorrow<Self::X> + Sized,

Sample a single value uniformly from a range with inclusive lower bound and inclusive upper bound `[low, high]`. Read more

source

### impl<X: Copy> Copy for UniformInt<X>

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### impl<X> StructuralPartialEq for UniformInt<X>

## Auto Trait Implementations

### impl<X> RefUnwindSafe for UniformInt<X> where
X: RefUnwindSafe,

### impl<X> Send for UniformInt<X> where
X: Send,

### impl<X> Sync for UniformInt<X> where
X: Sync,

### impl<X> Unpin for UniformInt<X> where
X: Unpin,

### impl<X> UnwindSafe for UniformInt<X> where
X: UnwindSafe,

## Blanket Implementations

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### impl<T> Any for T where
T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more

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### impl<T> Borrow<T> for T where
T: ?Sized,

const: unstable · source

#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more

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### impl<T> BorrowMut<T> for T where
T: ?Sized,

const: unstable · source

#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more

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### impl<T> From<T> for T

const: unstable · source

#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T, U> Into<U> for T where
U: From<T>,

const: unstable · source

#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T> ToOwned for T where
T: Clone,

#### type Owned = T

The resulting type after obtaining ownership.

source

#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more

source

#### fn clone_into(&self, target: &mut T)

🔬 This is a nightly-only experimental API. (`toowned_clone_into`)

Uses borrowed data to replace owned data, usually by cloning. Read more

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### impl<T, U> TryFrom<U> for T where
U: Into<T>,

#### type Error = Infallible

The type returned in the event of a conversion error.

const: unstable · source

#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.

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### impl<T, U> TryInto<U> for T where
U: TryFrom<T>,

#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.

const: unstable · source

#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.

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### impl<V, T> VZip<V> for T where
V: MultiLane<T>,

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#### fn vzip(self) -> V