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 });
RunIt 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 {
// ...
}
RunWhen 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 ]);
RunFields§
§end: Idx
The upper bound of the range (exclusive).
Implementations§
Trait Implementations§
source§impl<Idx: PartialEq> PartialEq for RangeTo<Idx>
impl<Idx: PartialEq> PartialEq for RangeTo<Idx>
1.28.0 · source§impl<T> RangeBounds<T> for RangeTo<&T>
impl<T> RangeBounds<T> for RangeTo<&T>
1.28.0 · source§impl<T> RangeBounds<T> for RangeTo<T>
impl<T> RangeBounds<T> for RangeTo<T>
1.15.0 (const: unstable) · source§impl<T> SliceIndex<[T]> for RangeTo<usize>
impl<T> SliceIndex<[T]> for RangeTo<usize>
const: unstable · source§fn get(self, slice: &[T]) -> Option<&[T]>
fn get(self, slice: &[T]) -> Option<&[T]>
slice_index_methods
)const: unstable · source§fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>
fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>
slice_index_methods
)const: unstable · source§unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]
unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]
slice_index_methods
)slice
pointer
is undefined behavior even if the resulting reference is not used.const: unstable · source§unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T]
unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T]
slice_index_methods
)slice
pointer
is undefined behavior even if the resulting reference is not used.1.20.0 (const: unstable) · source§impl 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 · source§fn get(self, slice: &str) -> Option<&Self::Output>
fn get(self, slice: &str) -> Option<&Self::Output>
slice_index_methods
)const: unstable · source§fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output>
fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output>
slice_index_methods
)const: unstable · source§unsafe fn get_unchecked(self, slice: *const str) -> *const Self::Output
unsafe fn get_unchecked(self, slice: *const str) -> *const Self::Output
slice_index_methods
)slice
pointer
is undefined behavior even if the resulting reference is not used.const: unstable · source§unsafe fn get_unchecked_mut(self, slice: *mut str) -> *mut Self::Output
unsafe fn get_unchecked_mut(self, slice: *mut str) -> *mut Self::Output
slice_index_methods
)slice
pointer
is undefined behavior even if the resulting reference is not used.