# Struct rand::distributions::Bernoulli

``pub struct Bernoulli { /* private fields */ }``
Expand description

The Bernoulli distribution.

This is a special case of the Binomial distribution where `n = 1`.

## §Example

``````use rand::distributions::{Bernoulli, Distribution};

let d = Bernoulli::new(0.3).unwrap();
let v = d.sample(&mut rand::thread_rng());
println!("{} is from a Bernoulli distribution", v);``````

## §Precision

This `Bernoulli` distribution uses 64 bits from the RNG (a `u64`), so only probabilities that are multiples of 2-64 can be represented.

## Implementations§

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### impl Bernoulli

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#### pub fn new(p: f64) -> Result<Bernoulli, BernoulliError>

Construct a new `Bernoulli` with the given probability of success `p`.

##### §Precision

For `p = 1.0`, the resulting distribution will always generate true. For `p = 0.0`, the resulting distribution will always generate false.

This method is accurate for any input `p` in the range `[0, 1]` which is a multiple of 2-64. (Note that not all multiples of 2-64 in `[0, 1]` can be represented as a `f64`.)

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#### pub fn from_ratio( numerator: u32, denominator: u32, ) -> Result<Bernoulli, BernoulliError>

Construct a new `Bernoulli` with the probability of success of `numerator`-in-`denominator`. I.e. `new_ratio(2, 3)` will return a `Bernoulli` with a 2-in-3 chance, or about 67%, of returning `true`.

return `true`. If `numerator == 0` it will always return `false`. For `numerator > denominator` and `denominator == 0`, this returns an error. Otherwise, for `numerator == denominator`, samples are always true; for `numerator == 0` samples are always false.

## Trait Implementations§

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### impl Clone for Bernoulli

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#### fn clone(&self) -> Bernoulli

Returns a copy of the value. Read more
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#### fn clone_from(&mut self, source: &Self)

Performs copy-assignment from `source`. Read more
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### impl Debug for Bernoulli

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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 Distribution<bool> for Bernoulli

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

Generate a random value of `T`, using `rng` as the source of randomness.
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#### fn sample_iter<R>(self, rng: R) -> DistIter<Self, R, T> ⓘwhere R: Rng, Self: Sized,

Create an iterator that generates random values of `T`, using `rng` as the source of randomness. Read more
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#### fn map<F, S>(self, func: F) -> DistMap<Self, F, T, S>where F: Fn(T) -> S, Self: Sized,

Create a distribution of values of ‘S’ by mapping the output of `Self` through the closure `F` Read more
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### impl PartialEq for Bernoulli

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#### fn eq(&self, other: &Bernoulli) -> bool

Tests for `self` and `other` values to be equal, and is used by `==`.
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#### fn ne(&self, other: &Rhs) -> bool

Tests for `!=`. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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## Blanket Implementations§

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### impl<T> Any for Twhere 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 Twhere T: ?Sized,

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

Immutably borrows from an owned value. Read more
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### impl<T> BorrowMut<T> for Twhere T: ?Sized,

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

Mutably borrows from an owned value. Read more
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### impl<T> CloneToUninit for Twhere T: Clone,

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#### default unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (`clone_to_uninit`)
Performs copy-assignment from `self` to `dst`. Read more
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### impl<T> CloneToUninit for Twhere T: Copy,

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#### unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (`clone_to_uninit`)
Performs copy-assignment from `self` to `dst`. Read more
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### impl<T> From<T> for T

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

Returns the argument unchanged.

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

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#### 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 Twhere T: Clone,

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#### type Owned = T

The resulting type after obtaining ownership.
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#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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#### fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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### impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### 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 Twhere U: TryFrom<T>,

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

The type returned in the event of a conversion error.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.
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