Trait IteratorExt 

pub trait IteratorExt: Iterator {
    // Required methods
    fn consume(self) -> Self
       where Self: Sized;
    fn drop(self, n: isize) -> Self
       where Self: Sized + DoubleEndedIterator;
    fn first(self) -> Option<Self::Item>
       where Self: Sized;
    fn first_result(self) -> RvResult<Self::Item>
       where Self: Sized;
    fn last_result(self) -> RvResult<Self::Item>
       where Self: Sized;
    fn single(self) -> RvResult<Self::Item>
       where Self: Sized;
    fn slice(self, left: isize, right: isize) -> Self
       where Self: Sized + Clone + DoubleEndedIterator;
    fn some(self) -> bool
       where Self: Sized;
}

Provides extensions for the Iterator trait

Required Methods

fn consume(self) -> Self

where Self: Sized,

Consume the entire iterator eagerly up until but not including the last call to get None. Allows caller to then call next and get None.

Examples

use rivia::prelude::*;

assert_eq!(vec![0, 1, 2].into_iter().consume().next(), None);

fn drop(self, n: isize) -> Self

where Self: Sized + DoubleEndedIterator,

Drop the first n items if positive from the iterator eagerly and then return the iterator. Drop the last |n| items if negative from the iterator eagerly and then return the iterator.

Examples

use rivia::prelude::*;

assert_iter_eq(vec![1, 2, 3].into_iter().drop(1), vec![2, 3]);
assert_iter_eq(vec![1, 2, 3].into_iter().drop(-1), vec![1, 2]);

fn first(self) -> Option<Self::Item>

where Self: Sized,

Returns the first element of the iterator. Alias to nth(0).

first() will return None if n is greater than or equal to the length of the iterator.

Examples

use rivia::prelude::*;

assert_eq!((0..10).filter(|&x| x == 2).first().unwrap(), 2);

fn first_result(self) -> RvResult<Self::Item>

where Self: Sized,

If the iterator yields at least one element, the first element will be returned, otherwise an error will be returned.

Examples

use rivia::prelude::*;

assert_eq!((0..10).filter(|&x| x == 2).first().unwrap(), 2);

fn last_result(self) -> RvResult<Self::Item>

where Self: Sized,

If the iterator yields at least one element, the last element will be returned, otherwise an error will be returned.

Examples

use rivia::prelude::*;

assert_eq!((0..10).filter(|&x| x == 2).last().unwrap(), 2);

fn single(self) -> RvResult<Self::Item>

where Self: Sized,

If the iterator yields a single element, that element will be returned, otherwise an error will be returned.

Examples

use rivia::prelude::*;

assert_eq!((0..10).filter(|&x| x == 2).single().unwrap(), 2);

fn slice(self, left: isize, right: isize) -> Self

where Self: Sized + Clone + DoubleEndedIterator,

Slice returns this iterator eagerly to only iterate over the range of elements called out by the given indices. Allows for negative notation.

Note this operation uses count() to determine length which means cost O(n) out of the gate.

Examples

use rivia::prelude::*;

let mut iter = vec![0, 1, 2].into_iter().slice(0, 0);
assert_eq!(iter.next(), Some(0));
assert_eq!(iter.next(), None);

let mut iter = vec![0, 1, 2].into_iter().slice(-1, -1);
assert_eq!(iter.next(), Some(2));
assert_eq!(iter.next(), None);

let mut iter = vec![0, 1, 2].into_iter().slice(-2, -1);
assert_eq!(iter.next(), Some(1));
assert_eq!(iter.next(), Some(2));
assert_eq!(iter.next(), None);

fn some(self) -> bool

where Self: Sized,

If the iterator yields at least one element, true will be returned else false

Examples

use rivia::prelude::*;

assert_eq!((0..10).filter(|&x| x == 2).some(), true);

Implementors

impl<T> IteratorExt for T

where T: Iterator + ?Sized,