1.0.0[−]Primitive Type bool
The boolean type.
The bool
represents a value, which could only be either true
or false
. If you cast
a bool
into an integer, true
will be 1 and false
will be 0.
Basic usage
bool
implements various traits, such as BitAnd
, BitOr
, Not
, etc.,
which allow us to perform boolean operations using &
, |
and !
.
if
always demands a bool
value. assert!
, being an important macro in testing,
checks whether an expression returns true
.
let bool_val = true & false | false; assert!(!bool_val);Run
Examples
A trivial example of the usage of bool
,
let praise_the_borrow_checker = true; // using the `if` conditional if praise_the_borrow_checker { println!("oh, yeah!"); } else { println!("what?!!"); } // ... or, a match pattern match praise_the_borrow_checker { true => println!("keep praising!"), false => println!("you should praise!"), }Run
Also, since bool
implements the Copy
trait, we don't
have to worry about the move semantics (just like the integer and float primitives).
Now an example of bool
cast to integer type:
assert_eq!(true as i32, 1); assert_eq!(false as i32, 0);Run
Methods
impl bool
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pub fn then<T>(self, t: T) -> Option<T>
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Returns Some(t)
if the bool
is true
, or None
otherwise.
Examples
#![feature(bool_to_option)] assert_eq!(false.then(0), None); assert_eq!(true.then(0), Some(0));Run
pub fn then_with<T, F>(self, f: F) -> Option<T> where
F: FnOnce() -> T,
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F: FnOnce() -> T,
Trait Implementations
impl<'a> BitOr<bool> for &'a bool
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type Output = <bool as BitOr<bool>>::Output
The resulting type after applying the |
operator.
fn bitor(self, other: bool) -> <bool as BitOr<bool>>::Output
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impl BitOr<bool> for bool
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type Output = bool
The resulting type after applying the |
operator.
fn bitor(self, rhs: bool) -> bool
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impl<'_, '_> BitOr<&'_ bool> for &'_ bool
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type Output = <bool as BitOr<bool>>::Output
The resulting type after applying the |
operator.
fn bitor(self, other: &bool) -> <bool as BitOr<bool>>::Output
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impl<'_> BitOr<&'_ bool> for bool
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type Output = <bool as BitOr<bool>>::Output
The resulting type after applying the |
operator.
fn bitor(self, other: &bool) -> <bool as BitOr<bool>>::Output
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impl Debug for bool
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impl FromStr for bool
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type Err = ParseBoolError
The associated error which can be returned from parsing.
fn from_str(s: &str) -> Result<bool, ParseBoolError>
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Parse a bool
from a string.
Yields a Result<bool, ParseBoolError>
, because s
may or may not
actually be parseable.
Examples
use std::str::FromStr; assert_eq!(FromStr::from_str("true"), Ok(true)); assert_eq!(FromStr::from_str("false"), Ok(false)); assert!(<bool as FromStr>::from_str("not even a boolean").is_err());Run
Note, in many cases, the .parse()
method on str
is more proper.
assert_eq!("true".parse(), Ok(true)); assert_eq!("false".parse(), Ok(false)); assert!("not even a boolean".parse::<bool>().is_err());Run
impl BitAnd<bool> for bool
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type Output = bool
The resulting type after applying the &
operator.
fn bitand(self, rhs: bool) -> bool
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impl<'_, '_> BitAnd<&'_ bool> for &'_ bool
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type Output = <bool as BitAnd<bool>>::Output
The resulting type after applying the &
operator.
fn bitand(self, other: &bool) -> <bool as BitAnd<bool>>::Output
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impl<'_> BitAnd<&'_ bool> for bool
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type Output = <bool as BitAnd<bool>>::Output
The resulting type after applying the &
operator.
fn bitand(self, other: &bool) -> <bool as BitAnd<bool>>::Output
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impl<'a> BitAnd<bool> for &'a bool
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type Output = <bool as BitAnd<bool>>::Output
The resulting type after applying the &
operator.
fn bitand(self, other: bool) -> <bool as BitAnd<bool>>::Output
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impl<'_> BitOrAssign<&'_ bool> for bool
1.22.0[src]
fn bitor_assign(&mut self, other: &bool)
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impl BitOrAssign<bool> for bool
1.8.0[src]
fn bitor_assign(&mut self, other: bool)
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impl Hash for bool
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fn hash<H>(&self, state: &mut H) where
H: Hasher,
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H: Hasher,
fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
1.3.0[src]
H: Hasher,
impl Eq for bool
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impl Clone for bool
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impl PartialEq<bool> for bool
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impl<'_> Not for &'_ bool
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type Output = <bool as Not>::Output
The resulting type after applying the !
operator.
fn not(self) -> <bool as Not>::Output
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impl Not for bool
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impl PartialOrd<bool> for bool
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fn partial_cmp(&self, other: &bool) -> Option<Ordering>
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#[must_use]
fn lt(&self, other: &Rhs) -> bool
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#[must_use]
fn le(&self, other: &Rhs) -> bool
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#[must_use]
fn gt(&self, other: &Rhs) -> bool
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#[must_use]
fn ge(&self, other: &Rhs) -> bool
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impl Default for bool
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impl BitAndAssign<bool> for bool
1.8.0[src]
fn bitand_assign(&mut self, other: bool)
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impl<'_> BitAndAssign<&'_ bool> for bool
1.22.0[src]
fn bitand_assign(&mut self, other: &bool)
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impl<'_> BitXor<&'_ bool> for bool
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type Output = <bool as BitXor<bool>>::Output
The resulting type after applying the ^
operator.
fn bitxor(self, other: &bool) -> <bool as BitXor<bool>>::Output
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impl<'a> BitXor<bool> for &'a bool
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type Output = <bool as BitXor<bool>>::Output
The resulting type after applying the ^
operator.
fn bitxor(self, other: bool) -> <bool as BitXor<bool>>::Output
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impl<'_, '_> BitXor<&'_ bool> for &'_ bool
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type Output = <bool as BitXor<bool>>::Output
The resulting type after applying the ^
operator.
fn bitxor(self, other: &bool) -> <bool as BitXor<bool>>::Output
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impl BitXor<bool> for bool
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type Output = bool
The resulting type after applying the ^
operator.
fn bitxor(self, other: bool) -> bool
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impl Display for bool
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impl Ord for bool
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fn cmp(&self, other: &bool) -> Ordering
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fn max(self, other: Self) -> Self
1.21.0[src]
fn min(self, other: Self) -> Self
1.21.0[src]
fn clamp(self, min: Self, max: Self) -> Self
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impl BitXorAssign<bool> for bool
1.8.0[src]
fn bitxor_assign(&mut self, other: bool)
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impl<'_> BitXorAssign<&'_ bool> for bool
1.22.0[src]
fn bitxor_assign(&mut self, other: &bool)
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impl Copy for bool
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Auto Trait Implementations
impl UnwindSafe for bool
impl RefUnwindSafe for bool
impl Unpin for bool
impl Send for bool
impl Sync for bool
Blanket Implementations
impl<T> From<T> for T
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
ⓘImportant traits for &'_ mut Ffn borrow_mut(&mut self) -> &mut T
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impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&self) -> T
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fn clone_into(&self, target: &mut T)
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impl<T> ToString for T where
T: Display + ?Sized,
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T: Display + ?Sized,