Struct std::ops::RangeTo

pub struct RangeTo<Idx> {
    pub end: Idx,
}

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

source

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

1.35.0source

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

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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

1.3.0source

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

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

1.3.0source

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 for RangeTo<Idx>
where
    Idx: PartialEq,

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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.

1.28.0source

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

1.35.0source

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

1.28.0source

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

1.35.0source

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: unstablesource

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: unstablesource

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: unstablesource

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: unstablesource

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: unstablesource

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: unstablesource

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.

type Output = str

The output type returned by methods.

const: unstablesource

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: unstablesource

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: unstablesource

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: unstablesource

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: unstablesource

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: unstablesource

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

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

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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> 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> ToOwned for T
where
    T: Clone,

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 T
where
    U: Into<T>,

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>,

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.

© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/ops/struct.RangeTo.html

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Struct std::ops::RangeTo

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