Struct lmdb_zero::CursorIter
[−]
[src]
pub struct CursorIter<'a, 'access: 'a, 'txn: 'access, 'db: 'txn, T> { /* fields omitted */ }
An iterator over items returned by successive calls of some function on
Cursor
until a NOTFOUND
error is returned.
Special handling is afforded the first item in the iterator, since the simple act of positioning the cursor produces the first item.
Methods
impl<'a, 'access: 'a, 'txn: 'access, 'db: 'txn, T> CursorIter<'a, 'access, 'txn, 'db, T>
[src]
pub fn new<H: FnOnce(&mut Cursor<'txn, 'db>, &'access ConstAccessor<'txn>) -> Result<T>>(
cursor: MaybeOwned<'a, Cursor<'txn, 'db>>,
access: &'access ConstAccessor<'txn>,
head: H,
next: fn(_: &mut Cursor<'txn, 'db>, _: &'access ConstAccessor<'txn>) -> Result<T>
) -> Result<Self>
[src]
cursor: MaybeOwned<'a, Cursor<'txn, 'db>>,
access: &'access ConstAccessor<'txn>,
head: H,
next: fn(_: &mut Cursor<'txn, 'db>, _: &'access ConstAccessor<'txn>) -> Result<T>
) -> Result<Self>
Creates a cursor iterator from the given cursor and accessor.
head
is invoked immediately on cursor
and accessor
to position
the cursor. The value it returns (if any) will be used as the first
value produced by the cursor.
Beyond the first item, next
will be invoked on cursor
and
accessor
to produce further items. Note that this is a plain function
pointer and not a function object so that the type does not need to be
encoded in the type of this iterator.
Example
let txn = lmdb::WriteTransaction::new(&env).unwrap(); { let mut access = txn.access(); let f = lmdb::put::Flags::empty(); access.put(&db, "Fruit", "Apple", f).unwrap(); access.put(&db, "Fruit", "Orange", f).unwrap(); access.put(&db, "Animal", "Badger", f).unwrap(); access.put(&db, "Veggie", "Carrot", f).unwrap(); let mut cursor = txn.cursor(&db).unwrap(); let mut iter = lmdb::CursorIter::new( lmdb::MaybeOwned::Borrowed(&mut cursor), &*access, |c, a| c.first(a), lmdb::Cursor::next::<str,str>).unwrap(); assert_eq!(("Animal", "Badger"), iter.next().unwrap().unwrap()); assert_eq!(("Fruit", "Apple"), iter.next().unwrap().unwrap()); assert_eq!(("Fruit", "Orange"), iter.next().unwrap().unwrap()); assert_eq!(("Veggie", "Carrot"), iter.next().unwrap().unwrap()); assert!(iter.next().is_none()); } txn.commit().unwrap();
Trait Implementations
impl<'a, 'access: 'a, 'txn: 'access, 'db: 'txn, T> Iterator for CursorIter<'a, 'access, 'txn, 'db, T>
[src]
type Item = Result<T>
The type of the elements being iterated over.
fn next(&mut self) -> Option<Result<T>>
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Advances the iterator and returns the next value. Read more
fn size_hint(&self) -> (usize, Option<usize>)
1.0.0[src]
Returns the bounds on the remaining length of the iterator. Read more
fn count(self) -> usize
1.0.0[src]
Consumes the iterator, counting the number of iterations and returning it. Read more
fn last(self) -> Option<Self::Item>
1.0.0[src]
Consumes the iterator, returning the last element. Read more
fn nth(&mut self, n: usize) -> Option<Self::Item>
1.0.0[src]
Returns the n
th element of the iterator. Read more
ⓘImportant traits for StepBy<I>fn step_by(self, step: usize) -> StepBy<Self>
[src]
🔬 This is a nightly-only experimental API. (iterator_step_by
)
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
ⓘImportant traits for Chain<A, B>fn chain<U>(self, other: U) -> Chain<Self, <U as IntoIterator>::IntoIter> where
U: IntoIterator<Item = Self::Item>,
1.0.0[src]
U: IntoIterator<Item = Self::Item>,
Takes two iterators and creates a new iterator over both in sequence. Read more
ⓘImportant traits for Zip<A, B>fn zip<U>(self, other: U) -> Zip<Self, <U as IntoIterator>::IntoIter> where
U: IntoIterator,
1.0.0[src]
U: IntoIterator,
'Zips up' two iterators into a single iterator of pairs. Read more
ⓘImportant traits for Map<I, F>fn map<B, F>(self, f: F) -> Map<Self, F> where
F: FnMut(Self::Item) -> B,
1.0.0[src]
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),
1.21.0[src]
F: FnMut(Self::Item),
Calls a closure on each element of an iterator. Read more
ⓘImportant traits for Filter<I, P>fn filter<P>(self, predicate: P) -> Filter<Self, P> where
P: FnMut(&Self::Item) -> bool,
1.0.0[src]
P: FnMut(&Self::Item) -> bool,
Creates an iterator which uses a closure to determine if an element should be yielded. Read more
ⓘImportant traits for FilterMap<I, F>fn filter_map<B, F>(self, f: F) -> FilterMap<Self, F> where
F: FnMut(Self::Item) -> Option<B>,
1.0.0[src]
F: FnMut(Self::Item) -> Option<B>,
Creates an iterator that both filters and maps. Read more
ⓘImportant traits for Enumerate<I>fn enumerate(self) -> Enumerate<Self>
1.0.0[src]
Creates an iterator which gives the current iteration count as well as the next value. Read more
ⓘImportant traits for Peekable<I>fn peekable(self) -> Peekable<Self>
1.0.0[src]
Creates an iterator which can use peek
to look at the next element of the iterator without consuming it. Read more
ⓘImportant traits for SkipWhile<I, P>fn skip_while<P>(self, predicate: P) -> SkipWhile<Self, P> where
P: FnMut(&Self::Item) -> bool,
1.0.0[src]
P: FnMut(&Self::Item) -> bool,
Creates an iterator that [skip
]s elements based on a predicate. Read more
ⓘImportant traits for TakeWhile<I, P>fn take_while<P>(self, predicate: P) -> TakeWhile<Self, P> where
P: FnMut(&Self::Item) -> bool,
1.0.0[src]
P: FnMut(&Self::Item) -> bool,
Creates an iterator that yields elements based on a predicate. Read more
ⓘImportant traits for Skip<I>fn skip(self, n: usize) -> Skip<Self>
1.0.0[src]
Creates an iterator that skips the first n
elements. Read more
ⓘImportant traits for Take<I>fn take(self, n: usize) -> Take<Self>
1.0.0[src]
Creates an iterator that yields its first n
elements. Read more
ⓘImportant traits for Scan<I, St, F>fn scan<St, B, F>(self, initial_state: St, f: F) -> Scan<Self, St, F> where
F: FnMut(&mut St, Self::Item) -> Option<B>,
1.0.0[src]
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
ⓘImportant traits for FlatMap<I, U, F>fn flat_map<U, F>(self, f: F) -> FlatMap<Self, U, F> where
F: FnMut(Self::Item) -> U,
U: IntoIterator,
1.0.0[src]
F: FnMut(Self::Item) -> U,
U: IntoIterator,
Creates an iterator that works like map, but flattens nested structure. Read more
ⓘImportant traits for Flatten<I>fn flatten(self) -> Flatten<Self> where
Self::Item: IntoIterator,
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Self::Item: IntoIterator,
iterator_flatten
)Creates an iterator that flattens nested structure. Read more
ⓘImportant traits for Fuse<I>fn fuse(self) -> Fuse<Self>
1.0.0[src]
Creates an iterator which ends after the first [None
]. Read more
ⓘImportant traits for Inspect<I, F>fn inspect<F>(self, f: F) -> Inspect<Self, F> where
F: FnMut(&Self::Item),
1.0.0[src]
F: FnMut(&Self::Item),
Do something with each element of an iterator, passing the value on. Read more
ⓘImportant traits for &'a mut Wfn by_ref(&mut self) -> &mut Self
1.0.0[src]
Borrows an iterator, rather than consuming it. Read more
fn collect<B>(self) -> B where
B: FromIterator<Self::Item>,
1.0.0[src]
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,
1.0.0[src]
B: Default + Extend<Self::Item>,
F: FnMut(&Self::Item) -> bool,
Consumes an iterator, creating two collections from it. Read more
fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R where
F: FnMut(B, Self::Item) -> R,
R: Try<Ok = B>,
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F: FnMut(B, Self::Item) -> R,
R: Try<Ok = B>,
iterator_try_fold
)An iterator method that applies a function as long as it returns successfully, producing a single, final value. Read more
fn try_for_each<F, R>(&mut self, f: F) -> R where
F: FnMut(Self::Item) -> R,
R: Try<Ok = ()>,
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F: FnMut(Self::Item) -> R,
R: Try<Ok = ()>,
iterator_try_fold
)An iterator method that applies a fallible function to each item in the iterator, stopping at the first error and returning that error. Read more
fn fold<B, F>(self, init: B, f: F) -> B where
F: FnMut(B, Self::Item) -> B,
1.0.0[src]
F: FnMut(B, Self::Item) -> B,
An iterator method 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,
1.0.0[src]
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,
1.0.0[src]
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,
1.0.0[src]
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,
1.0.0[src]
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,
1.0.0[src]
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,
1.0.0[src]
Self::Item: Ord,
Returns the maximum element of an iterator. Read more
fn min(self) -> Option<Self::Item> where
Self::Item: Ord,
1.0.0[src]
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[src]
B: Ord,
F: FnMut(&Self::Item) -> B,
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[src]
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
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[src]
B: Ord,
F: FnMut(&Self::Item) -> B,
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[src]
F: FnMut(&Self::Item, &Self::Item) -> Ordering,
Returns the element that gives the minimum value with respect to the specified comparison function. Read more
ⓘImportant traits for Rev<I>fn rev(self) -> Rev<Self> where
Self: DoubleEndedIterator,
1.0.0[src]
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)>,
1.0.0[src]
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
ⓘImportant traits for Cloned<I>fn cloned<'a, T>(self) -> Cloned<Self> where
Self: Iterator<Item = &'a T>,
T: 'a + Clone,
1.0.0[src]
Self: Iterator<Item = &'a T>,
T: 'a + Clone,
Creates an iterator which [clone
]s all of its elements. Read more
ⓘImportant traits for Cycle<I>fn cycle(self) -> Cycle<Self> where
Self: Clone,
1.0.0[src]
Self: Clone,
Repeats an iterator endlessly. Read more
fn sum<S>(self) -> S where
S: Sum<Self::Item>,
1.11.0[src]
S: Sum<Self::Item>,
Sums the elements of an iterator. Read more
fn product<P>(self) -> P where
P: Product<Self::Item>,
1.11.0[src]
P: Product<Self::Item>,
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[src]
I: IntoIterator<Item = Self::Item>,
Self::Item: Ord,
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[src]
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
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[src]
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
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[src]
I: IntoIterator,
Self::Item: PartialEq<<I as IntoIterator>::Item>,
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[src]
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
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[src]
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
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[src]
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
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[src]
I: IntoIterator,
Self::Item: PartialOrd<<I as IntoIterator>::Item>,
Determines if the elements of this Iterator
are lexicographically greater than or equal to those of another. Read more