Struct std::ops::RangeTo

1.0.0 · source ·
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 });
Run

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 {
    // ...
}
Run

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   ]);
Run

Fields§

§end: Idx

The upper bound of the range (exclusive).

Implementations§

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impl<Idx> RangeTo<Idx>where Idx: PartialOrd<Idx>,

1.35.0 · source

pub fn contains<U>(&self, item: &U) -> boolwhere 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));
Run

Trait Implementations§

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

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

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<Idx> Debug for RangeTo<Idx>where Idx: Debug,

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

Formats the value using the given formatter. Read more
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impl<Idx> Hash for RangeTo<Idx>where Idx: Hash,

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

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

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

Feeds a slice of this type into the given Hasher. Read more
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impl Index<RangeTo<usize>> for String

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type Output = str

The returned type after indexing.
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fn index(&self, index: RangeTo<usize>) -> &str

Performs the indexing (container[index]) operation. Read more
1.3.0 · source§

impl IndexMut<RangeTo<usize>> for String

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fn index_mut(&mut self, index: RangeTo<usize>) -> &mut str

Performs the mutable indexing (container[index]) operation. Read more
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impl<Idx> PartialEq<RangeTo<Idx>> for RangeTo<Idx>where Idx: PartialEq<Idx>,

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

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method 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) -> boolwhere T: PartialOrd<U>, U: PartialOrd<T> + ?Sized,

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) -> boolwhere T: PartialOrd<U>, U: PartialOrd<T> + ?Sized,

Returns true if item is contained in the range. Read more
1.15.0 (const: unstable) · source§

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

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type Output = [T]

The output type returned by methods.
const: unstable · source§

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.
const: unstable · source§

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.
const: unstable · source§

unsafe fn get_unchecked(self, slice: *const [T]) -> *const [T]

🔬This is a nightly-only experimental API. (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.
const: unstable · source§

unsafe fn get_unchecked_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, 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.
const: unstable · source§

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.
const: unstable · source§

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 (const: unstable) · 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.
const: unstable · source§

fn get( self, slice: &str ) -> Option<&<RangeTo<usize> as SliceIndex<str>>::Output>

🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a shared reference to the output at this location, if in bounds.
const: unstable · source§

fn get_mut( self, slice: &mut str ) -> Option<&mut <RangeTo<usize> as SliceIndex<str>>::Output>

🔬This is a nightly-only experimental API. (slice_index_methods)
Returns a mutable reference to the output at this location, if in bounds.
const: unstable · source§

unsafe fn get_unchecked( self, slice: *const str ) -> *const <RangeTo<usize> as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (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.
const: unstable · source§

unsafe fn get_unchecked_mut( self, slice: *mut str ) -> *mut <RangeTo<usize> as SliceIndex<str>>::Output

🔬This is a nightly-only experimental API. (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.
const: unstable · source§

fn index(self, slice: &str) -> &<RangeTo<usize> as SliceIndex<str>>::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.
const: unstable · source§

fn index_mut( self, slice: &mut str ) -> &mut <RangeTo<usize> as SliceIndex<str>>::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.
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impl<Idx> Copy for RangeTo<Idx>where Idx: Copy,

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

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

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impl<Idx> StructuralEq for RangeTo<Idx>

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impl<Idx> StructuralPartialEq for RangeTo<Idx>

Auto Trait Implementations§

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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 Twhere 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 Twhere 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 Twhere 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> 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 Twhere 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> ToOwned for Twhere T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for Twhere 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 Twhere 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.