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: IdxThe upper bound of the range (exclusive).
Implementations§
Trait Implementations§
source§impl<Idx> PartialEq for RangeTo<Idx>where
Idx: PartialEq,
impl<Idx> PartialEq for RangeTo<Idx>where
Idx: PartialEq,
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<&<RangeTo<usize> as SliceIndex<str>>::Output>
fn get( self, slice: &str ) -> Option<&<RangeTo<usize> as SliceIndex<str>>::Output>
slice_index_methods)const: unstable · source§fn 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)const: unstable · source§unsafe 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)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 <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)slice pointer
is undefined behavior even if the resulting reference is not used.