pub struct RangeTo<Idx> {
pub end: Idx,
}
Expand description
A range only bounded exclusively above (..end
).
The RangeTo
..end
contains all values with x < end
.
It cannot serve as an Iterator
because it doesn’t have a starting point.
Examples
The ..end
syntax is a RangeTo
:
assert_eq!((..5), std::ops::RangeTo { end: 5 });
It does not have an IntoIterator
implementation, so you can’t use it in
a for
loop directly. This won’t compile:
// error[E0277]: the trait bound `std::ops::RangeTo<{integer}>:
// std::iter::Iterator` is not satisfied
for i in ..5 {
// ...
}
When used as a slicing index, RangeTo
produces a slice of all array
elements before the index indicated by end
.
let arr = [0, 1, 2, 3, 4];
assert_eq!(arr[ .. ], [0, 1, 2, 3, 4]);
assert_eq!(arr[ .. 3], [0, 1, 2 ]); // This is a `RangeTo`
assert_eq!(arr[ ..=3], [0, 1, 2, 3 ]);
assert_eq!(arr[1.. ], [ 1, 2, 3, 4]);
assert_eq!(arr[1.. 3], [ 1, 2 ]);
assert_eq!(arr[1..=3], [ 1, 2, 3 ]);
Fields
end: Idx
The upper bound of the range (exclusive).
Implementations
sourceimpl<Idx> RangeTo<Idx> where
Idx: PartialOrd<Idx>,
impl<Idx> RangeTo<Idx> where
Idx: PartialOrd<Idx>,
1.35.0 · sourcepub fn contains<U>(&self, item: &U) -> bool where
Idx: PartialOrd<U>,
U: PartialOrd<Idx> + ?Sized,
pub fn contains<U>(&self, item: &U) -> bool where
Idx: PartialOrd<U>,
U: PartialOrd<Idx> + ?Sized,
Returns true
if item
is contained in the range.
Examples
assert!( (..5).contains(&-1_000_000_000));
assert!( (..5).contains(&4));
assert!(!(..5).contains(&5));
assert!( (..1.0).contains(&0.5));
assert!(!(..1.0).contains(&f32::NAN));
assert!(!(..f32::NAN).contains(&0.5));
Trait Implementations
1.28.0 · sourceimpl<'_, T> RangeBounds<T> for RangeTo<&'_ T>
impl<'_, T> RangeBounds<T> for RangeTo<&'_ T>
1.28.0 · sourceimpl<T> RangeBounds<T> for RangeTo<T>
impl<T> RangeBounds<T> for RangeTo<T>
1.15.0 (const: unstable) · sourceimpl<T> SliceIndex<[T]> for RangeTo<usize>
impl<T> SliceIndex<[T]> for RangeTo<usize>
const: unstable · sourcefn get(self, slice: &[T]) -> Option<&[T]>
fn get(self, slice: &[T]) -> Option<&[T]>
slice_index_methods
)Returns a shared reference to the output at this location, if in bounds. Read more
const: unstable · sourcefn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>
fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>
slice_index_methods
)Returns a mutable reference to the output at this location, if in bounds. Read more
const: unstable · sourceunsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]
unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]
slice_index_methods
)Returns a shared reference to the output at this location, without
performing any bounds checking.
Calling this method with an out-of-bounds index or a dangling slice
pointer
is undefined behavior even if the resulting reference is not used. Read more
const: unstable · sourceunsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T]
unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T]
slice_index_methods
)Returns a mutable reference to the output at this location, without
performing any bounds checking.
Calling this method with an out-of-bounds index or a dangling slice
pointer
is undefined behavior even if the resulting reference is not used. Read more
const: unstable · sourcefn index(self, slice: &[T]) -> &[T]ⓘNotable traits for &'_ [u8]impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]
fn index(self, slice: &[T]) -> &[T]ⓘNotable traits for &'_ [u8]impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]
slice_index_methods
)Returns a shared reference to the output at this location, panicking if out of bounds. Read more
const: unstable · sourcefn index_mut(self, slice: &mut [T]) -> &mut [T]ⓘNotable traits for &'_ [u8]impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]
fn index_mut(self, slice: &mut [T]) -> &mut [T]ⓘNotable traits for &'_ [u8]impl<'_> Read for &'_ [u8]impl<'_> Write for &'_ mut [u8]
slice_index_methods
)Returns a mutable reference to the output at this location, panicking if out of bounds. Read more
1.20.0 (const: unstable) · sourceimpl SliceIndex<str> for RangeTo<usize>
impl SliceIndex<str> for RangeTo<usize>
Implements substring slicing with syntax &self[.. end]
or &mut self[.. end]
.
Returns a slice of the given string from the byte range [0, end
).
Equivalent to &self[0 .. end]
or &mut self[0 .. end]
.
This operation is O(1).
Prior to 1.20.0, these indexing operations were still supported by
direct implementation of Index
and IndexMut
.
Panics
Panics if end
does not point to the starting byte offset of a
character (as defined by is_char_boundary
), or if end > len
.
const: unstable · sourcefn get(
self,
slice: &str
) -> Option<&<RangeTo<usize> as SliceIndex<str>>::Output>
fn get(
self,
slice: &str
) -> Option<&<RangeTo<usize> as SliceIndex<str>>::Output>
slice_index_methods
)Returns a shared reference to the output at this location, if in bounds. Read more
const: unstable · sourcefn get_mut(
self,
slice: &mut str
) -> Option<&mut <RangeTo<usize> as SliceIndex<str>>::Output>
fn get_mut(
self,
slice: &mut str
) -> Option<&mut <RangeTo<usize> as SliceIndex<str>>::Output>
slice_index_methods
)Returns a mutable reference to the output at this location, if in bounds. Read more
const: unstable · sourceunsafe fn get_unchecked(
self,
slice: *const str
) -> *const <RangeTo<usize> as SliceIndex<str>>::Output
unsafe fn get_unchecked(
self,
slice: *const str
) -> *const <RangeTo<usize> as SliceIndex<str>>::Output
slice_index_methods
)Returns a shared reference to the output at this location, without
performing any bounds checking.
Calling this method with an out-of-bounds index or a dangling slice
pointer
is undefined behavior even if the resulting reference is not used. Read more
const: unstable · sourceunsafe fn get_unchecked_mut(
self,
slice: *mut str
) -> *mut <RangeTo<usize> as SliceIndex<str>>::Output
unsafe fn get_unchecked_mut(
self,
slice: *mut str
) -> *mut <RangeTo<usize> as SliceIndex<str>>::Output
slice_index_methods
)Returns a mutable reference to the output at this location, without
performing any bounds checking.
Calling this method with an out-of-bounds index or a dangling slice
pointer
is undefined behavior even if the resulting reference is not used. Read more
impl<Idx> Copy for RangeTo<Idx> where
Idx: Copy,
impl<Idx> Eq for RangeTo<Idx> where
Idx: Eq,
impl<T> OneSidedRange<T> for RangeTo<T> where
RangeTo<T>: RangeBounds<T>,
impl<Idx> StructuralEq for RangeTo<Idx>
impl<Idx> StructuralPartialEq for RangeTo<Idx>
Auto Trait Implementations
impl<Idx> RefUnwindSafe for RangeTo<Idx> where
Idx: RefUnwindSafe,
impl<Idx> Send for RangeTo<Idx> where
Idx: Send,
impl<Idx> Sync for RangeTo<Idx> where
Idx: Sync,
impl<Idx> Unpin for RangeTo<Idx> where
Idx: Unpin,
impl<Idx> UnwindSafe for RangeTo<Idx> where
Idx: UnwindSafe,
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
sourceimpl<Q, K> Equivalent<K> for Q where
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
impl<Q, K> Equivalent<K> for Q where
Q: Eq + ?Sized,
K: Borrow<Q> + ?Sized,
sourcefn equivalent(&self, key: &K) -> bool
fn equivalent(&self, key: &K) -> bool
Compare self to key
and return true
if they are equal.
sourceimpl<T> ToOwned for T where
T: Clone,
impl<T> ToOwned for T where
T: Clone,
type Owned = T
type Owned = T
The resulting type after obtaining ownership.
sourcefn clone_into(&self, target: &mut T)
fn clone_into(&self, target: &mut T)
toowned_clone_into
)Uses borrowed data to replace owned data, usually by cloning. Read more