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.
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);
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);
impl PartialEq<bool> for bool
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fn eq(&self, other: &bool) -> boolThis method tests for self and other values to be equal, and is used by ==. Read more
fn ne(&self, other: &bool) -> boolThis method tests for !=.
impl Default for bool
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fn default() -> boolReturns the "default value" for a type. Read more
impl Clone for bool
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fn clone(&self) -> boolReturns a deep copy of the value.
fn clone_from(&mut self, source: &Self)Performs copy-assignment from source. Read more
impl Not for bool
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type Output = boolThe resulting type after applying the ! operator
fn not(self) -> boolThe method for the unary ! operator
impl<'a> Not for &'a bool
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type Output = bool::OutputThe resulting type after applying the ! operator
fn not(self) -> bool::OutputThe method for the unary ! operator
impl Display for bool
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fn fmt(&self, f: &mut Formatter) -> Result<(), Error>Formats the value using the given formatter.
impl Eq for bool
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impl FromStr for bool
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type Err = ParseBoolErrorThe associated error which can be returned from parsing.
fn from_str(s: &str) -> Result<bool, ParseBoolError>Parse a bool from a string.
Yields a Result<bool, ParseBoolError>, because s may or may not actually be parseable.
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()); impl BitXorAssign<bool> for bool
fn bitxor_assign(&mut self, other: bool)The method for the ^= operator
impl Debug for bool
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fn fmt(&self, f: &mut Formatter) -> Result<(), Error>Formats the value using the given formatter.
impl BitOrAssign<bool> for bool
fn bitor_assign(&mut self, other: bool)The method for the |= operator
impl Ord for bool
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fn cmp(&self, other: &bool) -> OrderingThis method returns an Ordering between self and other. Read more
impl BitXor<bool> for bool
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type Output = boolThe resulting type after applying the ^ operator
fn bitxor(self, other: bool) -> boolThe method for the ^ operator
impl<'a> BitXor<bool> for &'a bool
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type Output = bool::OutputThe resulting type after applying the ^ operator
fn bitxor(self, other: bool) -> bool::OutputThe method for the ^ operator
impl<'a> BitXor<&'a bool> for bool
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type Output = bool::OutputThe resulting type after applying the ^ operator
fn bitxor(self, other: &'a bool) -> bool::OutputThe method for the ^ operator
impl<'a, 'b> BitXor<&'a bool> for &'b bool
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type Output = bool::OutputThe resulting type after applying the ^ operator
fn bitxor(self, other: &'a bool) -> bool::OutputThe method for the ^ operator
impl BitOr<bool> for bool
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type Output = boolThe resulting type after applying the | operator
fn bitor(self, rhs: bool) -> boolThe method for the | operator
impl<'a> BitOr<bool> for &'a bool
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type Output = bool::OutputThe resulting type after applying the | operator
fn bitor(self, other: bool) -> bool::OutputThe method for the | operator
impl<'a> BitOr<&'a bool> for bool
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type Output = bool::OutputThe resulting type after applying the | operator
fn bitor(self, other: &'a bool) -> bool::OutputThe method for the | operator
impl<'a, 'b> BitOr<&'a bool> for &'b bool
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type Output = bool::OutputThe resulting type after applying the | operator
fn bitor(self, other: &'a bool) -> bool::OutputThe method for the | operator
impl Hash for bool
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fn hash<H>(&self, state: &mut H) where H: HasherFeeds this value into the state given, updating the hasher as necessary.
fn hash_slice<H>(data: &[Self], state: &mut H) where H: HasherFeeds a slice of this type into the state provided.
impl BitAnd<bool> for bool
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type Output = boolThe resulting type after applying the & operator
fn bitand(self, rhs: bool) -> boolThe method for the & operator
impl<'a> BitAnd<bool> for &'a bool
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type Output = bool::OutputThe resulting type after applying the & operator
fn bitand(self, other: bool) -> bool::OutputThe method for the & operator
impl<'a> BitAnd<&'a bool> for bool
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type Output = bool::OutputThe resulting type after applying the & operator
fn bitand(self, other: &'a bool) -> bool::OutputThe method for the & operator
impl<'a, 'b> BitAnd<&'a bool> for &'b bool
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type Output = bool::OutputThe resulting type after applying the & operator
fn bitand(self, other: &'a bool) -> bool::OutputThe method for the & operator
impl BitAndAssign<bool> for bool
fn bitand_assign(&mut self, other: bool)The method for the &= operator
impl PartialOrd<bool> for bool
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fn partial_cmp(&self, other: &bool) -> Option<Ordering>This method returns an ordering between self and other values if one exists. Read more
fn lt(&self, other: &Rhs) -> boolThis method tests less than (for self and other) and is used by the < operator. Read more
fn le(&self, other: &Rhs) -> boolThis method tests less than or equal to (for self and other) and is used by the <= operator. Read more
fn gt(&self, other: &Rhs) -> boolThis method tests greater than (for self and other) and is used by the > operator. Read more
fn ge(&self, other: &Rhs) -> boolThis method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
© 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