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:

i

// 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

source

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

1.35.0 · source

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));

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,

Feeds a slice of this type into the given Hasher. Read more

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impl Index<RangeTo<usize>> for String

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 ==. Read more

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

This method tests for !=.

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: 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) -> bool where
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>

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. Read more

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. Read more

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. Read more

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. Read more

const: unstable · source

fn index(self, slice: &[T]) -> &[T] iNotable traits for &[u8]impl Read for &[u8]impl Write for &mut [u8]

🔬 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. Read more

const: unstable · source

fn index_mut(self, slice: &mut [T]) -> &mut [T] iNotable traits for &[u8]impl Read for &[u8]impl Write for &mut [u8]

🔬 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. Read more

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.

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. Read more

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. Read more

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. Read more

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. Read more

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. Read more

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. Read more

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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>