std::ops::RangeTo - Rust
Description: API documentation for the Rust `RangeTo` struct in crate `std`.
Keywords: rust, rustlang, rust-lang, RangeTo

# Struct std::ops::RangeTo 1.0.0 [−] [src]

    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> RangeTo<Idx> where
Idx: PartialOrd<Idx>,`
[src]

#### `pub fn contains(&self, item: Idx) -> bool`
[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)]

    assert!( (..5).contains(-1_000_000_000));
    assert!( (..5).contains(4));
    assert!(!(..5).contains(5));Run

## Trait Implementations

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

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

The returned type after indexing.

####
ⓘImportant traits for &'a [u8]

### Important traits for &'a [u8]

`impl<'a> Read for &'a [u8]impl<'a> Write for &'a mut [u8]`
`fn index(&self, index: RangeTo<usize>) -> &[T]`
[src]

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

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

#### `type Output = str`

The returned type after indexing.

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

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

### `impl<T> RangeArgument<T> for RangeTo<T>`
[src]

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

🔬 This is a nightly-only experimental API. (`collections_range` #30877)

waiting for dust to settle on inclusive ranges

Start index bound. Read more

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

🔬 This is a nightly-only experimental API. (`collections_range` #30877)

waiting for dust to settle on inclusive ranges

End index bound. Read more

### `impl<T> IndexMut<RangeTo<usize>> for Vec<T>`
[src]

####
ⓘImportant traits for &'a [u8]

### Important traits for &'a [u8]

`impl<'a> Read for &'a [u8]impl<'a> Write for &'a mut [u8]`
`fn index_mut(&mut self, index: RangeTo<usize>) -> &mut [T]`
[src]

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

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

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

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

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

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

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

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

🔬 This is a nightly-only experimental API. (`slice_get_slice` #35729)

The output type returned by methods.

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

🔬 This is a nightly-only experimental API. (`slice_get_slice` #35729)

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_get_slice` #35729)

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

####
ⓘImportant traits for &'a [u8]

### Important traits for &'a [u8]

`impl<'a> Read for &'a [u8]impl<'a> Write for &'a mut [u8]`
`unsafe fn get_unchecked(self, slice: &[T]) -> &[T]`
[src]

🔬 This is a nightly-only experimental API. (`slice_get_slice` #35729)

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

####
ⓘImportant traits for &'a [u8]

### Important traits for &'a [u8]

`impl<'a> Read for &'a [u8]impl<'a> Write for &'a mut [u8]`
`unsafe fn get_unchecked_mut(self, slice: &mut [T]) -> &mut [T]`
[src]

🔬 This is a nightly-only experimental API. (`slice_get_slice` #35729)

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

####
ⓘImportant traits for &'a [u8]

### Important traits for &'a [u8]

`impl<'a> Read for &'a [u8]impl<'a> Write for &'a mut [u8]`
`fn index(self, slice: &[T]) -> &[T]`
[src]

🔬 This is a nightly-only experimental API. (`slice_get_slice` #35729)

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

####
ⓘImportant traits for &'a [u8]

### Important traits for &'a [u8]

`impl<'a> Read for &'a [u8]impl<'a> Write for &'a mut [u8]`
`fn index_mut(self, slice: &mut [T]) -> &mut [T]`
[src]

🔬 This is a nightly-only experimental API. (`slice_get_slice` #35729)

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`

🔬 This is a nightly-only experimental API. (`slice_get_slice` #35729)

The output type returned by methods.

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

🔬 This is a nightly-only experimental API. (`slice_get_slice` #35729)

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

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

🔬 This is a nightly-only experimental API. (`slice_get_slice` #35729)

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

#### `unsafe fn get_unchecked(
self,
slice: &str
) -> &<RangeTo<usize> as SliceIndex<str>>::Output`
[src]

🔬 This is a nightly-only experimental API. (`slice_get_slice` #35729)

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 <RangeTo<usize> as SliceIndex<str>>::Output`
[src]

🔬 This is a nightly-only experimental API. (`slice_get_slice` #35729)

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

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

🔬 This is a nightly-only experimental API. (`slice_get_slice` #35729)

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 <RangeTo<usize> as SliceIndex<str>>::Output`
[src]

🔬 This is a nightly-only experimental API. (`slice_get_slice` #35729)

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

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

#### `fn eq(&self, __arg_0: &RangeTo<Idx>) -> bool`
[src]

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

#### `fn ne(&self, __arg_0: &RangeTo<Idx>) -> bool`
[src]

This method tests for `!=`.

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

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

Formats the value using the given formatter. Read more

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

#### `fn hash<__HIdx>(&self, __arg_0: &mut __HIdx) where
__HIdx: Hasher,`
[src]

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

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

Feeds a slice of this type into the given [`Hasher`]. 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
+ / -
  Collapse/expand 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`)