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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);

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!"),
}

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);

Trait Implementations

impl Copy for bool[src]

impl<'a> BitXor<bool> for &'a bool[src]

type Output = <bool as BitXor<bool>>::Output

The resulting type after applying the ^ operator.

impl<'_, '_> BitXor<&'_ bool> for &'_ bool[src]

type Output = <bool as BitXor<bool>>::Output

The resulting type after applying the ^ operator.

impl BitXor<bool> for bool[src]

type Output = bool

The resulting type after applying the ^ operator.

impl<'_> BitXor<&'_ bool> for bool[src]

type Output = <bool as BitXor<bool>>::Output

The resulting type after applying the ^ operator.

impl BitXorAssign<bool> for bool[src]1.8.0

impl<'_> BitXorAssign<&'_ bool> for bool[src]1.22.0

impl Default for bool[src]

fn default() -> bool[src]

Returns the default value of false

impl Hash for bool[src]

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, [src]1.3.0

Feeds a slice of this type into the given [Hasher]. Read more

impl<'_> BitOr<&'_ bool> for bool[src]

type Output = <bool as BitOr<bool>>::Output

The resulting type after applying the | operator.

impl<'_, '_> BitOr<&'_ bool> for &'_ bool[src]

type Output = <bool as BitOr<bool>>::Output

The resulting type after applying the | operator.

impl<'a> BitOr<bool> for &'a bool[src]

type Output = <bool as BitOr<bool>>::Output

The resulting type after applying the | operator.

impl BitOr<bool> for bool[src]

type Output = bool

The resulting type after applying the | operator.

impl Clone for bool[src]

fn clone_from(&mut self, source: &Self)[src]

Performs copy-assignment from source. Read more

impl Eq for bool[src]

impl PartialOrd<bool> for bool[src]

fn lt(&self, other: &Rhs) -> bool[src]

This method tests less than (for self and other) and is used by the < operator. Read more

fn le(&self, other: &Rhs) -> bool[src]

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more

fn gt(&self, other: &Rhs) -> bool[src]

This method tests greater than (for self and other) and is used by the > operator. Read more

fn ge(&self, other: &Rhs) -> bool[src]

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

impl BitAnd<bool> for bool[src]

type Output = bool

The resulting type after applying the & operator.

impl<'_> BitAnd<&'_ bool> for bool[src]

type Output = <bool as BitAnd<bool>>::Output

The resulting type after applying the & operator.

impl<'_, '_> BitAnd<&'_ bool> for &'_ bool[src]

type Output = <bool as BitAnd<bool>>::Output

The resulting type after applying the & operator.

impl<'a> BitAnd<bool> for &'a bool[src]

type Output = <bool as BitAnd<bool>>::Output

The resulting type after applying the & operator.

impl<'_> BitOrAssign<&'_ bool> for bool[src]1.22.0

impl BitOrAssign<bool> for bool[src]1.8.0

impl Ord for bool[src]

fn max(self, other: Self) -> Self[src]1.21.0

Compares and returns the maximum of two values. Read more

fn min(self, other: Self) -> Self[src]1.21.0

Compares and returns the minimum of two values. Read more

fn clamp(self, min: Self, max: Self) -> Self[src]

🔬 This is a nightly-only experimental API. (clamp #44095)

Restrict a value to a certain interval. Read more

impl Debug for bool[src]

impl PartialEq<bool> for bool[src]

impl Display for bool[src]

impl BitAndAssign<bool> for bool[src]1.8.0

impl<'_> BitAndAssign<&'_ bool> for bool[src]1.22.0

impl<'_> Not for &'_ bool[src]

type Output = <bool as Not>::Output

The resulting type after applying the ! operator.

impl Not for bool[src]

type Output = bool

The resulting type after applying the ! operator.

impl FromStr for bool[src]

type Err = ParseBoolError

The associated error which can be returned from parsing.

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());

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());

© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/primitive.bool.html