Primitive Type bool1.0.0[−]
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
requires a bool
value as its conditional. assert!
, which is an
important macro in testing, checks whether an expression is true
and panics
if it isn’t.
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
Implementations
impl bool
[src]
impl bool
[src]pub fn then_some<T>(self, t: T) -> Option<T>
[src]
Returns Some(t)
if the bool
is true
, or None
otherwise.
Examples
#![feature(bool_to_option)] assert_eq!(false.then_some(0), None); assert_eq!(true.then_some(0), Some(0));Run
pub fn then<T, F>(self, f: F) -> Option<T> where
F: FnOnce() -> T,
1.50.0[src]
F: FnOnce() -> T,
Trait Implementations
impl<'_> BitAndAssign<&'_ bool> for bool
1.22.0[src]
impl<'_> BitAndAssign<&'_ bool> for bool
1.22.0[src]pub fn bitand_assign(&mut self, other: &bool)
[src]
impl BitAndAssign<bool> for bool
1.8.0[src]
impl BitAndAssign<bool> for bool
1.8.0[src]pub fn bitand_assign(&mut self, other: bool)
[src]
impl<'_> BitOrAssign<&'_ bool> for bool
1.22.0[src]
impl<'_> BitOrAssign<&'_ bool> for bool
1.22.0[src]pub fn bitor_assign(&mut self, other: &bool)
[src]
impl BitOrAssign<bool> for bool
1.8.0[src]
impl BitOrAssign<bool> for bool
1.8.0[src]pub fn bitor_assign(&mut self, other: bool)
[src]
impl<'_> BitXorAssign<&'_ bool> for bool
1.22.0[src]
impl<'_> BitXorAssign<&'_ bool> for bool
1.22.0[src]pub fn bitxor_assign(&mut self, other: &bool)
[src]
impl BitXorAssign<bool> for bool
1.8.0[src]
impl BitXorAssign<bool> for bool
1.8.0[src]pub fn bitxor_assign(&mut self, other: bool)
[src]
impl FromStr for bool
[src]
impl FromStr for bool
[src]type Err = ParseBoolError
The associated error which can be returned from parsing.
pub fn from_str(s: &str) -> Result<bool, ParseBoolError>
[src]
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 PartialOrd<bool> for bool
[src]
impl PartialOrd<bool> for bool
[src]impl Copy for bool
[src]
impl Eq for bool
[src]
Auto Trait Implementations
impl RefUnwindSafe for bool
impl Send for bool
impl Sync for bool
impl Unpin for bool
impl UnwindSafe for bool
Blanket Implementations
impl<T> Borrow<T> for T where
T: ?Sized,
[src]
impl<T> Borrow<T> for T where
T: ?Sized,
[src]pub fn borrow(&self) -> &TⓘNotable traits for &'_ mut I
impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
[src]
Notable traits for &'_ mut I
impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]
impl<T> BorrowMut<T> for T where
T: ?Sized,
[src]pub fn borrow_mut(&mut self) -> &mut TⓘNotable traits for &'_ mut I
impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W
[src]
Notable traits for &'_ mut I
impl<'_, I> Iterator for &'_ mut I where
I: Iterator + ?Sized, type Item = <I as Iterator>::Item;impl<'_, F> Future for &'_ mut F where
F: Future + Unpin + ?Sized, type Output = <F as Future>::Output;impl<R: Read + ?Sized> Read for &mut Rimpl<W: Write + ?Sized> Write for &mut W