core::range

Struct RangeTo

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pub struct RangeTo<Idx> {
    pub end: Idx,
}
🔬This is a nightly-only experimental API. (new_range_api #125687)
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
🔬This is a nightly-only experimental API. (new_range_api #125687)

The upper bound of the range (exclusive).

Implementations§

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impl<Idx: PartialOrd<Idx>> RangeTo<Idx>

1.35.0 · source

pub fn contains<U>(&self, item: &U) -> bool
where Idx: PartialOrd<U>, U: ?Sized + PartialOrd<Idx>,

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§

1.6.0 · source§

impl<Idx: Clone> Clone for RangeTo<Idx>

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fn clone(&self) -> RangeTo<Idx>

Returns a copy of the value. Read more
1.6.0 · source§

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
1.6.0 · source§

impl<Idx: Debug> Debug for RangeTo<Idx>

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fn fmt(&self, fmt: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
1.6.0 · source§

impl<Idx: Hash> Hash for RangeTo<Idx>

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fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher. Read more
1.6.0 · source§

fn hash_slice<H: Hasher>(data: &[Self], state: &mut H)
where Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
1.6.0 · source§

impl<Idx: PartialEq> PartialEq for RangeTo<Idx>

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fn eq(&self, other: &RangeTo<Idx>) -> bool

Tests for self and other values to be equal, and is used by ==.
1.6.0 · source§

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.28.0 · source§

impl<T> RangeBounds<T> for RangeTo<&T>

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fn start_bound(&self) -> Bound<&T>

Start index bound. Read more
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fn end_bound(&self) -> Bound<&T>

End index bound. Read more
1.35.0 · source§

fn contains<U>(&self, item: &U) -> bool
where T: PartialOrd<U>, U: ?Sized + PartialOrd<T>,

Returns true if item is contained in the range. Read more
1.28.0 · source§

impl<T> RangeBounds<T> for RangeTo<T>

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fn start_bound(&self) -> Bound<&T>

Start index bound. Read more
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fn end_bound(&self) -> Bound<&T>

End index bound. Read more
1.35.0 · source§

fn contains<U>(&self, item: &U) -> bool
where T: PartialOrd<U>, U: ?Sized + PartialOrd<T>,

Returns true if item is contained in the range. Read more
1.15.0 · source§

impl<T> SliceIndex<[T]> for RangeTo<usize>

The methods index and index_mut panic if the end of the range is out of bounds.

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type Output = [T]

The output type returned by methods.
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fn get(self, slice: &[T]) -> Option<&[T]>

🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a shared reference to the output at this location, if in bounds.
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fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>

🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a mutable reference to the output at this location, if in bounds.
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unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]

🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
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unsafe fn get_unchecked_mut(self, slice: *mut [T]) -> *mut [T]

🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
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fn index(self, slice: &[T]) -> &[T]

🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a shared reference to the output at this location, panicking if out of bounds.
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fn index_mut(self, slice: &mut [T]) -> &mut [T]

🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a mutable reference to the output at this location, panicking if out of bounds.
1.20.0 · source§

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.

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type Output = str

The output type returned by methods.
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fn get(self, slice: &str) -> Option<&Self::Output>

🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a shared reference to the output at this location, if in bounds.
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fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output>

🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a mutable reference to the output at this location, if in bounds.
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unsafe fn get_unchecked(self, slice: *const str) -> *const Self::Output

🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a pointer to the output at this location, without performing any bounds checking. Read more
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unsafe fn get_unchecked_mut(self, slice: *mut str) -> *mut Self::Output

🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a mutable pointer to the output at this location, without performing any bounds checking. Read more
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fn index(self, slice: &str) -> &Self::Output

🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a shared reference to the output at this location, panicking if out of bounds.
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fn index_mut(self, slice: &mut str) -> &mut Self::Output

🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a mutable reference to the output at this location, panicking if out of bounds.
1.6.0 · source§

impl<Idx: Copy> Copy for RangeTo<Idx>

1.6.0 · source§

impl<Idx: Eq> Eq for RangeTo<Idx>

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impl<T> OneSidedRange<T> for RangeTo<T>
where Self: RangeBounds<T>,

1.6.0 · source§

impl<Idx> StructuralPartialEq for RangeTo<Idx>

Auto Trait Implementations§

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impl<Idx> Freeze for RangeTo<Idx>
where Idx: Freeze,

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impl<Idx> RefUnwindSafe for RangeTo<Idx>
where Idx: RefUnwindSafe,

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impl<Idx> Send for RangeTo<Idx>
where Idx: Send,

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impl<Idx> Sync for RangeTo<Idx>
where Idx: Sync,

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impl<Idx> Unpin for RangeTo<Idx>
where Idx: Unpin,

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impl<Idx> UnwindSafe for RangeTo<Idx>
where Idx: UnwindSafe,

Blanket Implementations§

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impl<T> Any for T
where T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where T: ?Sized,

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fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where T: ?Sized,

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fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> CloneToUninit for T
where T: Clone,

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unsafe fn clone_to_uninit(&self, dst: *mut T)

🔬This is a nightly-only experimental API. (clone_to_uninit #126799)
Performs copy-assignment from self to dst. Read more
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impl<T> From<T> for T

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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where U: From<T>,

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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T, U> TryFrom<U> for T
where U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.