Primitive Type bool []

The boolean type.

The bool represents a value, which could only be either true or false.

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.

fn main() { let bool_val = true & false | false; assert!(!bool_val); }
let bool_val = true & false | false;
assert!(!bool_val);Run

Examples

A trivial example of the usage of bool,

fn main() { 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!"), } }
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).

Trait Implementations

impl PartialEq<bool> for bool
1.0.0

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
1.0.0

The resulting type after applying the ^ operator

The method for the ^ operator

impl<'a> BitXor<bool> for &'a bool
1.0.0

The resulting type after applying the ^ operator

The method for the ^ operator

impl<'a> BitXor<&'a bool> for bool
1.0.0

The resulting type after applying the ^ operator

The method for the ^ operator

impl<'a, 'b> BitXor<&'a bool> for &'b bool
1.0.0

The resulting type after applying the ^ operator

The method for the ^ operator

impl Default for bool
1.0.0

Returns the "default value" for a type. Read more

impl Clone for bool
1.0.0

Returns a deep copy of the value.

Performs copy-assignment from source. Read more

impl BitAnd<bool> for bool
1.0.0

The resulting type after applying the & operator

The method for the & operator

impl<'a> BitAnd<bool> for &'a bool
1.0.0

The resulting type after applying the & operator

The method for the & operator

impl<'a> BitAnd<&'a bool> for bool
1.0.0

The resulting type after applying the & operator

The method for the & operator

impl<'a, 'b> BitAnd<&'a bool> for &'b bool
1.0.0

The resulting type after applying the & operator

The method for the & operator

impl BitOrAssign<bool> for bool
1.8.0

The method for the |= operator

impl BitXorAssign<bool> for bool
1.8.0

The method for the ^= operator

impl Display for bool
1.0.0

Formats the value using the given formatter.

impl FromStr for bool
1.0.0

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

fn main() { 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()); }
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.

fn main() { assert_eq!("true".parse(), Ok(true)); assert_eq!("false".parse(), Ok(false)); assert!("not even a boolean".parse::<bool>().is_err()); }
assert_eq!("true".parse(), Ok(true));
assert_eq!("false".parse(), Ok(false));
assert!("not even a boolean".parse::<bool>().is_err());Run

impl BitOr<bool> for bool
1.0.0

The resulting type after applying the | operator

The method for the | operator

impl<'a> BitOr<bool> for &'a bool
1.0.0

The resulting type after applying the | operator

The method for the | operator

impl<'a> BitOr<&'a bool> for bool
1.0.0

The resulting type after applying the | operator

The method for the | operator

impl<'a, 'b> BitOr<&'a bool> for &'b bool
1.0.0

The resulting type after applying the | operator

The method for the | operator

impl Ord for bool
1.0.0

This method returns an Ordering between self and other. Read more

impl Debug for bool
1.0.0

Formats the value using the given formatter.

impl Not for bool
1.0.0

The resulting type after applying the ! operator

The method for the unary ! operator

impl<'a> Not for &'a bool
1.0.0

The resulting type after applying the ! operator

The method for the unary ! operator

impl Eq for bool
1.0.0

impl BitAndAssign<bool> for bool
1.8.0

The method for the & operator

impl Hash for bool
1.0.0

Feeds this value into the state given, updating the hasher as necessary.

Feeds a slice of this type into the state provided.

impl PartialOrd<bool> for bool
1.0.0

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