Trait RangeBounds

pub trait RangeBounds<T: ?Sized>

RangeBounds is implemented by Rust's built-in range types, produced by range syntax like .., a.., ..b, ..=c, d..e, or f..=g.

Required Methods

fn start_bound(&self) -> Bound<&T>

Start index bound.

Returns the start value as a Bound.

Examples

use std::ops::Bound::*;
use std::ops::RangeBounds;

assert_eq!((..10).start_bound(), Unbounded);
assert_eq!((3..10).start_bound(), Included(&3));

fn end_bound(&self) -> Bound<&T>

End index bound.

Returns the end value as a Bound.

Examples

use std::ops::Bound::*;
use std::ops::RangeBounds;

assert_eq!((3..).end_bound(), Unbounded);
assert_eq!((3..10).end_bound(), Excluded(&10));

Provided Methods

fn contains<U>(&self, item: &U) -> bool
where
    T: ~const PartialOrd<U>,
    U: ?Sized + ~const PartialOrd<T>,

Returns true if item is contained in the range.

Examples

assert!( (3..5).contains(&4));
assert!(!(3..5).contains(&2));

assert!( (0.0..1.0).contains(&0.5));
assert!(!(0.0..1.0).contains(&f32::NAN));
assert!(!(0.0..f32::NAN).contains(&0.5));
assert!(!(f32::NAN..1.0).contains(&0.5));

fn is_empty(&self) -> bool
where
    T: ~const PartialOrd,

Returns true if the range contains no items. One-sided ranges (RangeFrom, etc) always return false.

Examples

#![feature(range_bounds_is_empty)]
use std::ops::RangeBounds;

assert!(!(3..).is_empty());
assert!(!(..2).is_empty());
assert!(!RangeBounds::is_empty(&(3..5)));
assert!( RangeBounds::is_empty(&(3..3)));
assert!( RangeBounds::is_empty(&(3..2)));

The range is empty if either side is incomparable:

#![feature(range_bounds_is_empty)]
use std::ops::RangeBounds;

assert!(!RangeBounds::is_empty(&(3.0..5.0)));
assert!( RangeBounds::is_empty(&(3.0..f32::NAN)));
assert!( RangeBounds::is_empty(&(f32::NAN..5.0)));

But never empty if either side is unbounded:

#![feature(range_bounds_is_empty)]
use std::ops::RangeBounds;

assert!(!(..0).is_empty());
assert!(!(i32::MAX..).is_empty());
assert!(!RangeBounds::<u8>::is_empty(&(..)));

(Excluded(a), Excluded(b)) is only empty if a >= b:

#![feature(range_bounds_is_empty)]
use std::ops::Bound::*;
use std::ops::RangeBounds;

assert!(!(Excluded(1), Excluded(3)).is_empty());
assert!(!(Excluded(1), Excluded(2)).is_empty());
assert!( (Excluded(1), Excluded(1)).is_empty());
assert!( (Excluded(2), Excluded(1)).is_empty());
assert!( (Excluded(3), Excluded(1)).is_empty());

Implementors