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

# Struct std::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> RangeFrom<Idx> where
Idx: PartialOrd<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

## Trait Implementations

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

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

Formats the value using the given formatter.

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

### `impl<A> FusedIterator for RangeFrom<A> where
A: Step,`
[src]

### `impl<A> Iterator for RangeFrom<A> where
A: Step,`
[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 nth(&mut self, n: usize) -> Option<A>`

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

#### `fn count(self) -> usize`

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

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

Consumes the iterator, returning the last element. Read more

#### `fn step_by(self, step: usize) -> StepBy<Self>`

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

unstable replacement of Range::step_by

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

#### `fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter> where
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 as IntoIterator>::IntoIter> where
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
F: FnMut(Self::Item) -> B,`

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

#### `fn for_each<F>(self, f: F) where
F: FnMut(Self::Item) -> (),`

🔬 This is a nightly-only experimental API. (`iterator_for_each` #42986)

Calls a closure on each element of an iterator. Read more

#### `fn filter<P>(self, predicate: P) -> Filter<Self, P> where
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
F: FnMut(Self::Item) -> Option<B>,`

Creates an iterator that both filters and maps. Read more

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

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

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

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
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
P: FnMut(&Self::Item) -> bool,`

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

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

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

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

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
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
F: FnMut(Self::Item) -> U,
U: IntoIterator,`

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

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

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

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

Borrows an iterator, rather than consuming it. Read more

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

Transforms an iterator into a collection. Read more

#### `fn partition<B, F>(self, f: F) -> (B, B) where
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
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
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
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
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
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: 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::Item: Ord,`

Returns the maximum element of an iterator. Read more

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

Returns the minimum element of an iterator. Read more

#### `fn max_by_key<B, F>(self, f: F) -> Option<Self::Item> where
B: Ord,
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
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, F>(self, f: F) -> Option<Self::Item> where
B: Ord,
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
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: 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: Iterator<Item = (A, B)>,`

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

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

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

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

Repeats an iterator endlessly. Read more

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

Sums the elements of an iterator. Read more

#### `fn product<P>(self) -> P where
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,`
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 as IntoIterator>::Item>,`
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 as IntoIterator>::Item>,`
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 as IntoIterator>::Item>,`
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 as IntoIterator>::Item>,`
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 as IntoIterator>::Item>,`
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 as IntoIterator>::Item>,`
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 as IntoIterator>::Item>,`
1.5.0

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

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

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

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

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

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

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

🔬 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

### `impl SliceIndex<str> for RangeFrom<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<&<RangeFrom<usize> as SliceIndex<str>>::Output>`

🔬 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 <RangeFrom<usize> as SliceIndex<str>>::Output>`

🔬 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
) -> &<RangeFrom<usize> as SliceIndex<str>>::Output`

🔬 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 <RangeFrom<usize> as SliceIndex<str>>::Output`

🔬 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) -> &<RangeFrom<usize> as SliceIndex<str>>::Output`

🔬 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 <RangeFrom<usize> as SliceIndex<str>>::Output`

🔬 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<RangeFrom<Idx>> for RangeFrom<Idx> where
Idx: PartialEq<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<T> RangeArgument<T> for RangeFrom<T>`
[src]

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

🔬 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>`

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

waiting for dust to settle on inclusive ranges

End index bound. Read more

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