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: IdxThe 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, 
Trait Implementations
1.28.0 · sourceimpl<T> RangeBounds<T> for RangeTo<T>
 
impl<T> RangeBounds<T> for RangeTo<T>
sourcepub fn start_bound(&self) -> Bound<&T>
 
pub fn start_bound(&self) -> Bound<&T>
Start index bound. Read more
1.35.0 · sourcefn contains<U>(&self, item: &U) -> bool where
    T: PartialOrd<U>,
    U: PartialOrd<T> + ?Sized, 
 
fn contains<U>(&self, item: &U) -> bool where
    T: PartialOrd<U>,
    U: PartialOrd<T> + ?Sized, 
Returns true if item is contained in the range. Read more
1.28.0 · sourceimpl<'_, T> RangeBounds<T> for RangeTo<&'_ T>
 
impl<'_, T> RangeBounds<T> for RangeTo<&'_ T>
sourcepub fn start_bound(&self) -> Bound<&T>
 
pub fn start_bound(&self) -> Bound<&T>
Start index bound. Read more
1.35.0 · sourcefn contains<U>(&self, item: &U) -> bool where
    T: PartialOrd<U>,
    U: PartialOrd<T> + ?Sized, 
 
fn contains<U>(&self, item: &U) -> bool where
    T: PartialOrd<U>,
    U: PartialOrd<T> + ?Sized, 
Returns true if item is contained in the range. Read more
1.15.0 · sourceimpl<T> SliceIndex<[T]> for RangeTo<usize>
 
impl<T> SliceIndex<[T]> for RangeTo<usize>
sourcepub fn get(self, slice: &[T]) -> Option<&[T]>
 
pub 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
sourcepub fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>
 
pub 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
sourcepub unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]
 
pub 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
sourcepub unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T]
 
pub 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
1.20.0 · 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.
sourcepub fn get(
    self, 
    slice: &str
) -> Option<&<RangeTo<usize> as SliceIndex<str>>::Output>
 
pub 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
sourcepub fn get_mut(
    self, 
    slice: &mut str
) -> Option<&mut <RangeTo<usize> as SliceIndex<str>>::Output>
 
pub 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
sourcepub unsafe fn get_unchecked(
    self, 
    slice: *const str
) -> *const <RangeTo<usize> as SliceIndex<str>>::Output
 
pub 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
sourcepub unsafe fn get_unchecked_mut(
    self, 
    slice: *mut str
) -> *mut <RangeTo<usize> as SliceIndex<str>>::Output
 
pub 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 · sourcepub fn borrow_mut(&mut self) -> &mut T
 
pub fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more