# 1.0.0[−][src]Struct core::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 });Run

It does not have an `IntoIterator` implementation, so you can't use it in a `for` loop directly. This won't compile:

ⓘThis example deliberately fails to 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];
    assert_eq!(arr[ .. ], [0,1,2,3]);
    assert_eq!(arr[ ..3], [0,1,2  ]);  // RangeTo
    assert_eq!(arr[1.. ], [  1,2,3]);
    assert_eq!(arr[1..3], [  1,2  ]);Run

## Fields

`end: Idx`

The upper bound of the range (exclusive).

## Methods

### `impl<Idx: PartialOrd<Idx>> RangeTo<Idx>`[src]

#### `pub fn contains<U: ?Sized>(&self, item: &U) -> bool where
Idx: PartialOrd<U>,
U: PartialOrd<Idx>,` [src]

🔬 This is a nightly-only experimental API. (`range_contains` #32311)

recently added as per RFC

Returns `true` if `item` is contained in the range.

# Examples

    #![feature(range_contains)]

    use std::f32;

    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

### `impl<Idx: Copy> Copy for RangeTo<Idx>`[src]

### `impl Index<RangeTo<usize>> for str`[src]

Implements substring slicing with syntax `&self[.. end]`.

Returns a slice of the string from the beginning to byte offset `end`.

Equivalent to `&self[0 .. end]`.

#### `type Output = str`

The returned type after indexing.

#### `fn index(&self, index: RangeTo<usize>) -> &str`[src]

Performs the indexing (`container[index]`) operation.

### `impl IndexMut<RangeTo<usize>> for str`
1.3.0
[src]

Implements mutable substring slicing with syntax `&mut self[.. end]`.

Returns a mutable slice of the string from the beginning to byte offset `end`.

Equivalent to `&mut self[0 .. end]`.

#### `fn index_mut(&mut self, index: RangeTo<usize>) -> &mut str`[src]

Performs the mutable indexing (`container[index]`) operation.

### `impl<T> RangeBounds<T> for RangeTo<T>`
1.28.0
[src]

#### `fn start_bound(&self) -> Bound<&T>`[src]

Start index bound. Read more

#### `fn end_bound(&self) -> Bound<&T>`[src]

End index bound. Read more

#### `fn contains<U: ?Sized>(&self, item: &U) -> bool where
T: PartialOrd<U>,
U: PartialOrd<T>,` [src]

🔬 This is a nightly-only experimental API. (`range_contains` #32311)

recently added as per RFC

Returns `true` if `item` is contained in the range. Read more

### `impl<T, '_> RangeBounds<T> for RangeTo<&'_ T>`
1.28.0
[src]

#### `fn start_bound(&self) -> Bound<&T>`[src]

Start index bound. Read more

#### `fn end_bound(&self) -> Bound<&T>`[src]

End index bound. Read more

#### `fn contains<U: ?Sized>(&self, item: &U) -> bool where
T: PartialOrd<U>,
U: PartialOrd<T>,` [src]

🔬 This is a nightly-only experimental API. (`range_contains` #32311)

recently added as per RFC

Returns `true` if `item` is contained in the range. Read more

### `impl<Idx: PartialEq> PartialEq<RangeTo<Idx>> for RangeTo<Idx>`[src]

#### `fn eq(&self, other: &RangeTo<Idx>) -> bool`[src]

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `fn ne(&self, other: &RangeTo<Idx>) -> bool`[src]

This method tests for `!=`.

### `impl<Idx: Eq> Eq for RangeTo<Idx>`[src]

### `impl<Idx: Clone> Clone for RangeTo<Idx>`[src]

#### `fn clone(&self) -> RangeTo<Idx>`[src]

Returns a copy of the value. Read more

#### `fn clone_from(&mut self, source: &Self)`[src]

Performs copy-assignment from `source`. Read more

### `impl<T> SliceIndex<[T]> for RangeTo<usize>`
1.15.0
[src]

#### `type Output = [T]`

The output type returned by methods.

#### `fn get(self, slice: &[T]) -> Option<&[T]>`[src]

🔬 This is a nightly-only experimental API. (`slice_index_methods` #0)

Returns a shared reference to the output at this location, if in bounds. Read more

#### `fn get_mut(self, slice: &mut [T]) -> Option<&mut [T]>`[src]

🔬 This is a nightly-only experimental API. (`slice_index_methods` #0)

Returns a mutable reference to the output at this location, if in bounds. Read more

#### `unsafe fn get_unchecked(self, slice: &[T]) -> &[T]`[src]

🔬 This is a nightly-only experimental API. (`slice_index_methods` #0)

Returns a shared reference to the output at this location, without performing any bounds checking. Read more

#### `unsafe fn get_unchecked_mut(self, slice: &mut [T]) -> &mut [T]`[src]

🔬 This is a nightly-only experimental API. (`slice_index_methods` #0)

Returns a mutable reference to the output at this location, without performing any bounds checking. Read more

#### `fn index(self, slice: &[T]) -> &[T]`[src]

🔬 This is a nightly-only experimental API. (`slice_index_methods` #0)

Returns a shared reference to the output at this location, panicking if out of bounds. Read more

#### `fn index_mut(self, slice: &mut [T]) -> &mut [T]`[src]

🔬 This is a nightly-only experimental API. (`slice_index_methods` #0)

Returns a mutable reference to the output at this location, panicking if out of bounds. Read more

### `impl SliceIndex<str> for RangeTo<usize>`
1.20.0
[src]

#### `type Output = str`

The output type returned by methods.

#### `fn get(self, slice: &str) -> Option<&Self::Output>`[src]

🔬 This is a nightly-only experimental API. (`slice_index_methods` #0)

Returns a shared reference to the output at this location, if in bounds. Read more

#### `fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output>`[src]

🔬 This is a nightly-only experimental API. (`slice_index_methods` #0)

Returns a mutable reference to the output at this location, if in bounds. Read more

#### `unsafe fn get_unchecked(self, slice: &str) -> &Self::Output`[src]

🔬 This is a nightly-only experimental API. (`slice_index_methods` #0)

Returns a shared reference to the output at this location, without performing any bounds checking. Read more

#### `unsafe fn get_unchecked_mut(self, slice: &mut str) -> &mut Self::Output`[src]

🔬 This is a nightly-only experimental API. (`slice_index_methods` #0)

Returns a mutable reference to the output at this location, without performing any bounds checking. Read more

#### `fn index(self, slice: &str) -> &Self::Output`[src]

🔬 This is a nightly-only experimental API. (`slice_index_methods` #0)

Returns a shared reference to the output at this location, panicking if out of bounds. Read more

#### `fn index_mut(self, slice: &mut str) -> &mut Self::Output`[src]

🔬 This is a nightly-only experimental API. (`slice_index_methods` #0)

Returns a mutable reference to the output at this location, panicking if out of bounds. Read more

### `impl<Idx: Hash> Hash for RangeTo<Idx>`[src]

#### `fn hash<__HIdx: Hasher>(&self, state: &mut __HIdx)`[src]

Feeds this value into the given [`Hasher`]. Read more

#### `fn hash_slice<H: Hasher>(data: &[Self], state: &mut H) where
Self: Sized,`
1.3.0
[src]

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

### `impl<Idx: Debug> Debug for RangeTo<Idx>`[src]

#### `fn fmt(&self, fmt: &mut Formatter) -> Result`[src]

Formats the value using the given formatter. Read more

## Auto Trait Implementations

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

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

## Blanket Implementations

### `impl<T, U> Into for T where
U: From<T>,` [src]

#### `fn into(Self) -> U`[src]

Performs the conversion.

### `impl<T> From for T`[src]

#### `fn from(T) -> T`[src]

Performs the conversion.

### `impl<T, U> TryInto for T where
U: TryFrom<T>,` [src]

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

🔬 This is a nightly-only experimental API. (`try_from` #33417)

The type returned in the event of a conversion error.

#### `fn try_into(Self) -> Result<U, <U as TryFrom<T>>::Error>`[src]

🔬 This is a nightly-only experimental API. (`try_from` #33417)

Performs the conversion.

### `impl<T, U> TryFrom for T where
T: From<U>,` [src]

#### `type Error = !`

🔬 This is a nightly-only experimental API. (`try_from` #33417)

The type returned in the event of a conversion error.

#### `fn try_from(U) -> Result<T, <T as TryFrom<U>>::Error>`[src]

🔬 This is a nightly-only experimental API. (`try_from` #33417)

Performs the conversion.

### `impl<T> Borrow for T where
T: ?Sized,` [src]

#### `fn borrow(&Self) -> &T`[src]

Immutably borrows from an owned value. Read more

### `impl<T> BorrowMut for T where
T: ?Sized,` [src]

#### `fn borrow_mut(&mut Self) -> &mut T`[src]

Mutably borrows from an owned value. Read more

### `impl<T> Any for T where
T: 'static + ?Sized,` [src]

#### `fn get_type_id(&Self) -> TypeId`[src]

🔬 This is a nightly-only experimental API. (`get_type_id` #27745)

this method will likely be replaced by an associated static

Gets the `TypeId` of `self`. Read more

# Help

## Keyboard Shortcuts

`?`
  Show this help dialog
`S`
  Focus the search field
`↑`
  Move up in search results
`↓`
  Move down in search results
`↹`
  Switch tab
`⏎`
  Go to active search result
`+`
  Expand all sections
`-`
  Collapse all sections

## Search Tricks

Prefix searches with a type followed by a colon (e.g., `fn:`) to restrict the search to a given type.

Accepted types are: `fn`, `mod`, `struct`, `enum`, `trait`, `type`, `macro`, and `const`.

Search functions by type signature (e.g., `vec -> usize` or `* -> vec`)

Search multiple things at once by splitting your query with comma (e.g., `str,u8` or `String,struct:Vec,test`)