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 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 PartialEq<bool> for bool
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This method tests for self and other values to be equal, and is used by ==. Read more

This method tests for !=.

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

The method for the ^ operator

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

The method for the ^ operator

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

The method for the ^ operator

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

The method for the ^ operator

impl Clone for bool
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Returns a deep copy of the value.

Performs copy-assignment from source. Read more

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

The method for the unary ! operator

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

The method for the unary ! operator

impl PartialOrd<bool> for bool
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This method returns an ordering between self and other values if one exists. Read more

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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Formats the value using the given formatter. Read more

impl Hash for bool
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Feeds this value into the state given, updating the hasher as necessary.

Feeds a slice of this type into the state provided.

impl BitOrAssign<bool> for bool
1.8.0
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The method for the |= operator

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

The method for the | operator

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

The method for the | operator

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

The method for the | operator

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

The method for the | operator

impl Eq for bool
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impl Default for bool
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Returns the "default value" for a type. Read more

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

The method for the & operator

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

The method for the & operator

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

The method for the & operator

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

The method for the & operator

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 BitXorAssign<bool> for bool
1.8.0
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The method for the ^= operator

impl BitAndAssign<bool> for bool
1.8.0
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The method for the &= operator

impl Debug for bool
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Formats the value using the given formatter.

impl Ord for bool
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This method returns an Ordering between self and other. Read more