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
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
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
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
slice_index_methods
)Returns a shared reference to the output at this location, if in bounds. Read more
slice_index_methods
)Returns a mutable reference to the output at this location, if in bounds. Read more
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
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
slice_index_methods
)Returns a shared reference to the output at this location, panicking if out of bounds. Read more
slice_index_methods
)Returns a mutable reference to the output at this location, panicking if out of bounds. Read more
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
.
slice_index_methods
)Returns a shared reference to the output at this location, if in bounds. Read more
slice_index_methods
)Returns a mutable reference to the output at this location, if in bounds. Read more
pub 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
pub 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
slice_index_methods
)Returns a shared reference to the output at this location, panicking if out of bounds. Read more
Auto Trait Implementations
impl<Idx> RefUnwindSafe for RangeTo<Idx> where
Idx: RefUnwindSafe,
impl<Idx> UnwindSafe for RangeTo<Idx> where
Idx: UnwindSafe,
Blanket Implementations
Mutably borrows from an owned value. Read more