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

Trait Implementations

impl Clone for bool
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Performs copy-assignment from source. Read more

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

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

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

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

impl Display for bool
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impl<'a> BitXorAssign<&'a bool> for bool
1.22.0
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impl BitXorAssign<bool> for bool
1.8.0
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impl Ord for bool
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Compares and returns the maximum of two values. Read more

Compares and returns the minimum of two values. Read more

impl<'a> BitOrAssign<&'a bool> for bool
1.22.0
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impl BitOrAssign<bool> for bool
1.8.0
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impl<'a> BitAndAssign<&'a bool> for bool
1.22.0
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impl BitAndAssign<bool> for bool
1.8.0
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impl Eq for bool
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impl FromStr for bool
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The associated error which can be returned from parsing.

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 PartialEq<bool> for bool
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impl<'a> BitOr<bool> for &'a bool
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The resulting type after applying the | operator.

impl<'a> BitOr<&'a bool> for bool
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The resulting type after applying the | operator.

impl BitOr<bool> for bool
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The resulting type after applying the | operator.

impl<'a, 'b> BitOr<&'a bool> for &'b bool
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The resulting type after applying the | operator.

impl Hash for bool
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Feeds a slice of this type into the given [Hasher]. Read more

impl Debug for bool
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impl BitXor<bool> for bool
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The resulting type after applying the ^ operator.

impl<'a, 'b> BitXor<&'a bool> for &'b bool
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The resulting type after applying the ^ operator.

impl<'a> BitXor<bool> for &'a bool
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The resulting type after applying the ^ operator.

impl<'a> BitXor<&'a bool> for bool
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The resulting type after applying the ^ operator.

impl<'a> Not for &'a bool
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The resulting type after applying the ! operator.

impl Not for bool
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The resulting type after applying the ! operator.

impl Default for bool
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Returns the default value of false

impl Copy for bool
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impl<'a> BitAnd<&'a bool> for bool
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The resulting type after applying the & operator.

impl BitAnd<bool> for bool
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The resulting type after applying the & operator.

impl<'a> BitAnd<bool> for &'a bool
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The resulting type after applying the & operator.

impl<'a, 'b> BitAnd<&'a bool> for &'b bool
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The resulting type after applying the & operator.