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

# Struct core::ops::RangeFrom 1.0.0 [−] [src]

    pub struct RangeFrom<Idx> {
        pub start: Idx,
    }

A range which is only bounded below: { x | start <= x }. Use `start..` for its shorthand.

See the `contains()` method for its characterization.

Note: Currently, no overflow checking is done for the iterator implementation; if you use an integer range and the integer overflows, it might panic in debug mode or create an endless loop in release mode. This overflow behavior might change in the future.

# Examples

    fn main() {
        assert_eq!((2..), std::ops::RangeFrom{ start: 2 });
        assert_eq!(2+3+4, (2..).take(3).sum());

        let arr = [0, 1, 2, 3];
        assert_eq!(arr[ .. ], [0,1,2,3]);
        assert_eq!(arr[ ..3], [0,1,2  ]);
        assert_eq!(arr[1.. ], [  1,2,3]);  // RangeFrom
        assert_eq!(arr[1..3], [  1,2  ]);
    }Run

## Fields

`start: Idx`

The lower bound of the range (inclusive).

## Methods

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

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

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

recently added as per RFC

# Examples

    #![feature(range_contains)]
    fn main() {
        assert!( ! (3..).contains(2));
        assert!(   (3..).contains(3));
        assert!(   (3..).contains(1_000_000_000));
    }Run

### `impl<A: Step> RangeFrom<A>`
[src]

#### `fn step_by(self, by: A) -> StepBy<A, Self>`

🔬 This is a nightly-only experimental API. (`step_by` #27741)

recent addition

Creates an iterator starting at the same point, but stepping by the given amount at each iteration.

# Examples

    #![feature(step_by)]
    fn main() {
        let result: Vec<_> = (0..).step_by(2).take(5).collect();
        assert_eq!(result, vec![0, 2, 4, 6, 8]);
    }Run

## Trait Implementations

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

#### `fn clone(&self) -> RangeFrom<Idx>`

Returns a copy of the value. Read more

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

Performs copy-assignment from `source`. Read more

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

#### `fn eq(&self, __arg_0: &RangeFrom<Idx>) -> bool`

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

#### `fn ne(&self, __arg_0: &RangeFrom<Idx>) -> bool`

This method tests for `!=`.

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

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

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

Feeds this value into the state given, updating the hasher as necessary.

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

Feeds a slice of this type into the state provided.

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

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

Formats the value using the given formatter.

### `impl<A: Step> Iterator for RangeFrom<A> where &'a A: Add<&'a A, Output=A>`
[src]

#### `type Item = A`

The type of the elements being iterated over.

#### `fn next(&mut self) -> Option<A>`

Advances the iterator and returns the next value. Read more

#### `fn size_hint(&self) -> (usize, Option<usize>)`

Returns the bounds on the remaining length of the iterator. Read more

#### `fn count(self) -> usize where Self: Sized`

Consumes the iterator, counting the number of iterations and returning it. Read more

#### `fn last(self) -> Option<Self::Item> where Self: Sized`

Consumes the iterator, returning the last element. Read more

#### `fn nth(&mut self, n: usize) -> Option<Self::Item>`

Returns the `n`th element of the iterator. Read more

#### `fn chain<U>(self, other: U) -> Chain<Self, U::IntoIter> where Self: Sized, U: IntoIterator<Item=Self::Item>`

Takes two iterators and creates a new iterator over both in sequence. Read more

#### `fn zip<U>(self, other: U) -> Zip<Self, U::IntoIter> where Self: Sized, U: IntoIterator`

'Zips up' two iterators into a single iterator of pairs. Read more

#### `fn map<B, F>(self, f: F) -> Map<Self, F> where Self: Sized, F: FnMut(Self::Item) -> B`

Takes a closure and creates an iterator which calls that closure on each element. Read more

#### `fn filter<P>(self, predicate: P) -> Filter<Self, P> where Self: Sized, P: FnMut(&Self::Item) -> bool`

Creates an iterator which uses a closure to determine if an element should be yielded. Read more

#### `fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F> where Self: Sized, F: FnMut(Self::Item) -> Option<B>`

Creates an iterator that both filters and maps. Read more

#### `fn enumerate(self) -> Enumerate<Self> where Self: Sized`

Creates an iterator which gives the current iteration count as well as the next value. Read more

#### `fn peekable(self) -> Peekable<Self> where Self: Sized`

Creates an iterator which can use `peek` to look at the next element of the iterator without consuming it. Read more

#### `fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where Self: Sized, P: FnMut(&Self::Item) -> bool`

Creates an iterator that [`skip()`]s elements based on a predicate. Read more

#### `fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where Self: Sized, P: FnMut(&Self::Item) -> bool`

Creates an iterator that yields elements based on a predicate. Read more

#### `fn skip(self, n: usize) -> Skip<Self> where Self: Sized`

Creates an iterator that skips the first `n` elements. Read more

#### `fn take(self, n: usize) -> Take<Self> where Self: Sized`

Creates an iterator that yields its first `n` elements. Read more

#### `fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where Self: Sized, F: FnMut(&mut St, Self::Item) -> Option<B>`

An iterator adaptor similar to [`fold()`] that holds internal state and produces a new iterator. Read more

#### `fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> where Self: Sized, U: IntoIterator, F: FnMut(Self::Item) -> U`

Creates an iterator that works like map, but flattens nested structure. Read more

#### `fn fuse(self) -> Fuse<Self> where Self: Sized`

Creates an iterator which ends after the first [`None`]. Read more

#### `fn inspect<F>(self, f: F) -> Inspect<Self, F> where Self: Sized, F: FnMut(&Self::Item)`

Do something with each element of an iterator, passing the value on. Read more

#### `fn by_ref(&mut self) -> &mut Self where Self: Sized`

Borrows an iterator, rather than consuming it. Read more

#### `fn collect<B: FromIterator<Self::Item>>(self) -> B where Self: Sized`

Transforms an iterator into a collection. Read more

#### `fn partition<B, F>(self, f: F) -> (B, B) where Self: Sized,
B: Default + Extend<Self::Item>,
F: FnMut(&Self::Item) -> bool`

Consumes an iterator, creating two collections from it. Read more

#### `fn fold<B, F>(self, init: B, f: F) -> B where Self: Sized, F: FnMut(B, Self::Item) -> B`

An iterator adaptor that applies a function, producing a single, final value. Read more

#### `fn all<F>(&mut self, f: F) -> bool where Self: Sized, F: FnMut(Self::Item) -> bool`

Tests if every element of the iterator matches a predicate. Read more

#### `fn any<F>(&mut self, f: F) -> bool where Self: Sized, F: FnMut(Self::Item) -> bool`

Tests if any element of the iterator matches a predicate. Read more

#### `fn find<P>(&mut self, predicate: P) -> Option<Self::Item> where Self: Sized, P: FnMut(&Self::Item) -> bool`

Searches for an element of an iterator that satisfies a predicate. Read more

#### `fn position<P>(&mut self, predicate: P) -> Option<usize> where Self: Sized, P: FnMut(Self::Item) -> bool`

Searches for an element in an iterator, returning its index. Read more

#### `fn rposition<P>(&mut self, predicate: P) -> Option<usize> where P: FnMut(Self::Item) -> bool,
Self: Sized + ExactSizeIterator + DoubleEndedIterator`

Searches for an element in an iterator from the right, returning its index. Read more

#### `fn max(self) -> Option<Self::Item> where Self: Sized, Self::Item: Ord`

Returns the maximum element of an iterator. Read more

#### `fn min(self) -> Option<Self::Item> where Self: Sized, Self::Item: Ord`

Returns the minimum element of an iterator. Read more

#### `fn max_by_key<B: Ord, F>(self, f: F) -> Option<Self::Item> where Self: Sized, F: FnMut(&Self::Item) -> B`
1.6.0

Returns the element that gives the maximum value from the specified function. Read more

#### `fn max_by<F>(self, compare: F) -> Option<Self::Item> where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering`
1.15.0

Returns the element that gives the maximum value with respect to the specified comparison function. Read more

#### `fn min_by_key<B: Ord, F>(self, f: F) -> Option<Self::Item> where Self: Sized, F: FnMut(&Self::Item) -> B`
1.6.0

Returns the element that gives the minimum value from the specified function. Read more

#### `fn min_by<F>(self, compare: F) -> Option<Self::Item> where Self: Sized, F: FnMut(&Self::Item, &Self::Item) -> Ordering`
1.15.0

Returns the element that gives the minimum value with respect to the specified comparison function. Read more

#### `fn rev(self) -> Rev<Self> where Self: Sized + DoubleEndedIterator`

Reverses an iterator's direction. Read more

#### `fn unzip<A, B, FromA, FromB>(self) -> (FromA, FromB) where FromA: Default + Extend<A>,
FromB: Default + Extend<B>,
Self: Sized + Iterator<Item=(A, B)>`

Converts an iterator of pairs into a pair of containers. Read more

#### `fn cloned<'a, T: 'a>(self) -> Cloned<Self> where Self: Sized + Iterator<Item=&'a T>, T: Clone`

Creates an iterator which [`clone()`]s all of its elements. Read more

#### `fn cycle(self) -> Cycle<Self> where Self: Sized + Clone`

Repeats an iterator endlessly. Read more

#### `fn sum<S>(self) -> S where Self: Sized, S: Sum<Self::Item>`
1.11.0

Sums the elements of an iterator. Read more

#### `fn product<P>(self) -> P where Self: Sized, P: Product<Self::Item>`
1.11.0

Iterates over the entire iterator, multiplying all the elements Read more

#### `fn cmp<I>(self, other: I) -> Ordering where I: IntoIterator<Item=Self::Item>, Self::Item: Ord, Self: Sized`
1.5.0

Lexicographically compares the elements of this `Iterator` with those of another. Read more

#### `fn partial_cmp<I>(self, other: I) -> Option<Ordering> where I: IntoIterator, Self::Item: PartialOrd<I::Item>, Self: Sized`
1.5.0

Lexicographically compares the elements of this `Iterator` with those of another. Read more

#### `fn eq<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialEq<I::Item>, Self: Sized`
1.5.0

Determines if the elements of this `Iterator` are equal to those of another. Read more

#### `fn ne<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialEq<I::Item>, Self: Sized`
1.5.0

Determines if the elements of this `Iterator` are unequal to those of another. Read more

#### `fn lt<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item>, Self: Sized`
1.5.0

Determines if the elements of this `Iterator` are lexicographically less than those of another. Read more

#### `fn le<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item>, Self: Sized`
1.5.0

Determines if the elements of this `Iterator` are lexicographically less or equal to those of another. Read more

#### `fn gt<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item>, Self: Sized`
1.5.0

Determines if the elements of this `Iterator` are lexicographically greater than those of another. Read more

#### `fn ge<I>(self, other: I) -> bool where I: IntoIterator, Self::Item: PartialOrd<I::Item>, Self: Sized`
1.5.0

Determines if the elements of this `Iterator` are lexicographically greater than or equal to those of another. Read more

### `impl<A> FusedIterator for RangeFrom<A> where A: Step,
&'a A: Add<&'a A, Output=A>`
[src]

### `impl<T> SliceIndex<T> for RangeFrom<usize>`
1.13.0
[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]>`

🔬 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]>`

🔬 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: &[T]) -> &[T]`

🔬 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 [T]) -> &mut [T]`

🔬 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: &[T]) -> &[T]`

🔬 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 [T]) -> &mut [T]`

🔬 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

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