Struct core::ops::RangeFrom

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

A range only bounded inclusively below (start..).

The RangeFrom start.. contains all values with x >= start.

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

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

let arr = [0, 1, 2, 3, 4];
assert_eq!(arr[ ..  ], [0,1,2,3,4]);
assert_eq!(arr[ .. 3], [0,1,2    ]);
assert_eq!(arr[ ..=3], [0,1,2,3  ]);
assert_eq!(arr[1..  ], [  1,2,3,4]);  // RangeFrom
assert_eq!(arr[1.. 3], [  1,2    ]);
assert_eq!(arr[1..=3], [  1,2,3  ]);

Fields

start: Idx

The lower bound of the range (inclusive).

Methods

impl<Idx: PartialOrd<Idx>> RangeFrom<Idx>

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

Returns true if item is contained in the range.

Examples

use std::f32;

assert!(!(3..).contains(&2));
assert!( (3..).contains(&3));
assert!( (3..).contains(&1_000_000_000));

assert!( (0.0..).contains(&0.5));
assert!(!(0.0..).contains(&f32::NAN));
assert!(!(f32::NAN..).contains(&0.5));

Trait Implementations

impl<T> RangeBounds<T> for RangeFrom<T>

fn start_bound(&self) -> Bound<&T>

Start index bound.

fn end_bound(&self) -> Bound<&T>

End index bound.

fn contains<U: ?Sized>(&self, item: &U) -> bool where
    T: PartialOrd<U>,
    U: PartialOrd<T>, 

Returns true if item is contained in the range.

impl<'_, T> RangeBounds<T> for RangeFrom<&'_ T>

fn start_bound(&self) -> Bound<&T>

Start index bound.

fn end_bound(&self) -> Bound<&T>

End index bound.

fn contains<U: ?Sized>(&self, item: &U) -> bool where
    T: PartialOrd<U>,
    U: PartialOrd<T>, 

Returns true if item is contained in the range.

impl<Idx: PartialEq> PartialEq<RangeFrom<Idx>> for RangeFrom<Idx>

fn eq(&self, other: &RangeFrom<Idx>) -> bool

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

fn ne(&self, other: &RangeFrom<Idx>) -> bool

This method tests for !=.

impl<Idx: Eq> Eq for RangeFrom<Idx>

impl<Idx: Clone> Clone for RangeFrom<Idx>

Important traits for RangeFrom<A>

impl<A: Step> Iterator for RangeFrom<A> type Item = A;

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

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<A: Step> Iterator for RangeFrom<A>

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.

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

Returns the bounds on the remaining length of the iterator.

fn nth(&mut self, n: usize) -> Option<A>

Returns the nth element of the iterator.

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

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

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

Consumes the iterator, returning the last element.

Important traits for StepBy<I>

impl<I> Iterator for StepBy<I> where
    I: Iterator,  type Item = I::Item;

fn step_by(self, step: usize) -> StepBy<Self> where
    Self: Sized, 

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

Important traits for Chain<A, B>

impl<A, B> Iterator for Chain<A, B> where
    A: Iterator,
    B: Iterator<Item = A::Item>,  type Item = A::Item;

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.

Important traits for Zip<A, B>

impl<A, B> Iterator for Zip<A, B> where
    A: Iterator,
    B: Iterator,  type Item = (A::Item, B::Item);

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.

Important traits for Map<I, F>

impl<B, I: Iterator, F> Iterator for Map<I, F> where
    F: FnMut(I::Item) -> B,  type Item = B;

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.

fn for_each<F>(self, f: F) where
    Self: Sized,
    F: FnMut(Self::Item), 

Calls a closure on each element of an iterator.

Important traits for Filter<I, P>

impl<I: Iterator, P> Iterator for Filter<I, P> where
    P: FnMut(&I::Item) -> bool,  type Item = I::Item;

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.

Important traits for FilterMap<I, F>

impl<B, I: Iterator, F> Iterator for FilterMap<I, F> where
    F: FnMut(I::Item) -> Option<B>,  type Item = B;

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.

Important traits for Enumerate<I>

impl<I> Iterator for Enumerate<I> where
    I: Iterator,  type Item = (usize, <I as Iterator>::Item);

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

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

Important traits for Peekable<I>

impl<I: Iterator> Iterator for Peekable<I> type Item = I::Item;

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.

Important traits for SkipWhile<I, P>

impl<I: Iterator, P> Iterator for SkipWhile<I, P> where
    P: FnMut(&I::Item) -> bool,  type Item = I::Item;

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.

Important traits for TakeWhile<I, P>

impl<I: Iterator, P> Iterator for TakeWhile<I, P> where
    P: FnMut(&I::Item) -> bool,  type Item = I::Item;

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.

Important traits for Skip<I>

impl<I> Iterator for Skip<I> where
    I: Iterator,  type Item = <I as Iterator>::Item;

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

Creates an iterator that skips the first n elements.

Important traits for Take<I>

impl<I> Iterator for Take<I> where
    I: Iterator,  type Item = <I as Iterator>::Item;

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

Creates an iterator that yields its first n elements.

Important traits for Scan<I, St, F>

impl<B, I, St, F> Iterator for Scan<I, St, F> where
    I: Iterator,
    F: FnMut(&mut St, I::Item) -> Option<B>,  type Item = B;

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.

Important traits for FlatMap<I, U, F>

impl<I: Iterator, U: IntoIterator, F> Iterator for FlatMap<I, U, F> where
    F: FnMut(I::Item) -> U,  type Item = U::Item;

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.

Important traits for Flatten<I>

impl<I, U> Iterator for Flatten<I> where
    I: Iterator<Item: IntoIterator<IntoIter = U, Item = U::Item>>,
    U: Iterator,  type Item = U::Item;

fn flatten(self) -> Flatten<Self> where
    Self: Sized,
    Self::Item: IntoIterator, 

Creates an iterator that flattens nested structure.

Important traits for Fuse<I>

impl<I> Iterator for Fuse<I> where
    I: Iterator,  type Item = <I as Iterator>::Item;impl<I> Iterator for Fuse<I> where
    I: FusedIterator, 

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

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

Important traits for Inspect<I, F>

impl<I: Iterator, F> Iterator for Inspect<I, F> where
    F: FnMut(&I::Item),  type Item = I::Item;

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.

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

Borrows an iterator, rather than consuming it.

#[must_use = "if you really need to exhaust the iterator, consider `.for_each(drop)` instead"] fn collect<B: FromIterator<Self::Item>>(self) -> B where
    Self: Sized, 

Transforms an iterator into a collection.

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.

fn partition_in_place<'a, T: 'a, P>(self, predicate: P) -> usize where
    Self: Sized + DoubleEndedIterator<Item = &'a mut T>,
    P: FnMut(&T) -> bool, 

🔬 This is a nightly-only experimental API. (iter_partition_in_place #62543)

new API

Reorder the elements of this iterator in-place according to the given predicate, such that all those that return true precede all those that return false. Returns the number of true elements found.

fn is_partitioned<P>(self, predicate: P) -> bool where
    Self: Sized,
    P: FnMut(Self::Item) -> bool, 

🔬 This is a nightly-only experimental API. (iter_is_partitioned #62544)

new API

Checks if the elements of this iterator are partitioned according to the given predicate, such that all those that return true precede all those that return false.

fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
    Self: Sized,
    F: FnMut(B, Self::Item) -> R,
    R: Try<Ok = B>, 

An iterator method that applies a function as long as it returns successfully, producing a single, final value.

fn try_for_each<F, R>(&mut self, f: F) -> R where
    Self: Sized,
    F: FnMut(Self::Item) -> R,
    R: Try<Ok = ()>, 

An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error.

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

An iterator method that applies a function, producing a single, final value.

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.

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.

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.

fn find_map<B, F>(&mut self, f: F) -> Option<B> where
    Self: Sized,
    F: FnMut(Self::Item) -> Option<B>, 

Applies function to the elements of iterator and returns the first non-none result.

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.

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.

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

Returns the maximum element of an iterator.

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

Returns the minimum element of an iterator.

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

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

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

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

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

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

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

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

Important traits for Rev<I>

impl<I> Iterator for Rev<I> where
    I: DoubleEndedIterator,  type Item = <I as Iterator>::Item;

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

Reverses an iterator's direction.

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.

Important traits for Copied<I>

impl<'a, I, T: 'a> Iterator for Copied<I> where
    I: Iterator<Item = &'a T>,
    T: Copy,  type Item = T;

fn copied<'a, T: 'a>(self) -> Copied<Self> where
    Self: Sized + Iterator<Item = &'a T>,
    T: Copy, 

Creates an iterator which copies all of its elements.

Important traits for Cloned<I>

impl<'a, I, T: 'a> Iterator for Cloned<I> where
    I: Iterator<Item = &'a T>,
    T: Clone,  type Item = T;

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.

Important traits for Cycle<I>

impl<I> Iterator for Cycle<I> where
    I: Clone + Iterator,  type Item = <I as Iterator>::Item;

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

Repeats an iterator endlessly.

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

Sums the elements of an iterator.

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

Iterates over the entire iterator, multiplying all the elements

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

Lexicographically compares the elements of this Iterator with those of another.

fn cmp_by<I, F>(self, other: I, cmp: F) -> Ordering where
    Self: Sized,
    I: IntoIterator,
    F: FnMut(Self::Item, I::Item) -> Ordering, 

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

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

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

Lexicographically compares the elements of this Iterator with those of another.

fn partial_cmp_by<I, F>(self, other: I, partial_cmp: F) -> Option<Ordering> where
    Self: Sized,
    I: IntoIterator,
    F: FnMut(Self::Item, I::Item) -> Option<Ordering>, 

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

Lexicographically compares the elements of this Iterator with those of another with respect to the specified comparison function.

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

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

fn eq_by<I, F>(self, other: I, eq: F) -> bool where
    Self: Sized,
    I: IntoIterator,
    F: FnMut(Self::Item, I::Item) -> bool, 

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

Determines if the elements of this Iterator are equal to those of another with respect to the specified equality function.

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

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

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

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

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

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

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

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

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

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

fn is_sorted(self) -> bool where
    Self: Sized,
    Self::Item: PartialOrd, 

🔬 This is a nightly-only experimental API. (is_sorted #53485)

new API

Checks if the elements of this iterator are sorted.

fn is_sorted_by<F>(self, compare: F) -> bool where
    Self: Sized,
    F: FnMut(&Self::Item, &Self::Item) -> Option<Ordering>, 

🔬 This is a nightly-only experimental API. (is_sorted #53485)

new API

Checks if the elements of this iterator are sorted using the given comparator function.

fn is_sorted_by_key<F, K>(self, f: F) -> bool where
    Self: Sized,
    F: FnMut(Self::Item) -> K,
    K: PartialOrd, 

🔬 This is a nightly-only experimental API. (is_sorted #53485)

new API

Checks if the elements of this iterator are sorted using the given key extraction function.

impl<A: Step> FusedIterator for RangeFrom<A>

impl<A: Step> TrustedLen for RangeFrom<A>

impl<T> SliceIndex<[T]> for RangeFrom<usize>

type Output = [T]

The output type returned by methods.

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

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

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

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

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

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

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

🔬 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. Calling this method with an out-of-bounds index is [undefined behavior] even if the resulting reference is not used. [undefined behavior]: ../../reference/behavior-considered-undefined.html

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

🔬 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. Calling this method with an out-of-bounds index is [undefined behavior] even if the resulting reference is not used. [undefined behavior]: ../../reference/behavior-considered-undefined.html

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

🔬 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.

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

🔬 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.

impl SliceIndex<str> for RangeFrom<usize>

Implements substring slicing with syntax &self[begin ..] or &mut self[begin ..].

Returns a slice of the given string from the byte range [begin, len). Equivalent to &self[begin .. len] or &mut self[begin .. len].

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 begin does not point to the starting byte offset of a character (as defined by is_char_boundary), or if begin >= len.

type Output = str

The output type returned by methods.

fn get(self, slice: &str) -> Option<&Self::Output>

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

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

fn get_mut(self, slice: &mut str) -> Option<&mut Self::Output>

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

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

unsafe fn get_unchecked(self, slice: &str) -> &Self::Output

🔬 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. Calling this method with an out-of-bounds index is [undefined behavior] even if the resulting reference is not used. [undefined behavior]: ../../reference/behavior-considered-undefined.html

unsafe fn get_unchecked_mut(self, slice: &mut str) -> &mut Self::Output

🔬 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. Calling this method with an out-of-bounds index is [undefined behavior] even if the resulting reference is not used. [undefined behavior]: ../../reference/behavior-considered-undefined.html

fn index(self, slice: &str) -> &Self::Output

🔬 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.

fn index_mut(self, slice: &mut str) -> &mut Self::Output

🔬 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.

impl<Idx: Hash> Hash for RangeFrom<Idx>

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given [Hasher].

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

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

impl<Idx: Debug> Debug for RangeFrom<Idx>

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

Formats the value using the given formatter.