Struct Cursor

pub struct Cursor<'a, K, V>
where
    K: 'a,
    V: 'a,
{ /* private fields */ }

🔬This is a nightly-only experimental API. (btree_cursors)

Available on crate feature dep_allocator_api2 only.

A cursor over a BTreeMap.

A Cursor is like an iterator, except that it can freely seek back-and-forth.

Cursors always point to a gap between two elements in the map, and can operate on the two immediately adjacent elements.

A Cursor is created with the BTreeMap::lower_bound and BTreeMap::upper_bound methods.

Implementations

impl<'a, K, V> Cursor<'a, K, V>

pub fn next(&mut self) -> Option<(&'a K, &'a V)>

🔬This is a nightly-only experimental API. (btree_cursors)

Available on crate feature alloc only.

Advances the cursor to the next gap, returning the key and value of the element that it moved over.

If the cursor is already at the end of the map then None is returned and the cursor is not moved.

pub fn prev(&mut self) -> Option<(&'a K, &'a V)>

🔬This is a nightly-only experimental API. (btree_cursors)

Available on crate feature alloc only.

Advances the cursor to the previous gap, returning the key and value of the element that it moved over.

If the cursor is already at the start of the map then None is returned and the cursor is not moved.

pub fn peek_next(&self) -> Option<(&'a K, &'a V)>

🔬This is a nightly-only experimental API. (btree_cursors)

Available on crate feature alloc only.

Returns a reference to the key and value of the next element without moving the cursor.

If the cursor is at the end of the map then None is returned.

pub fn peek_prev(&self) -> Option<(&'a K, &'a V)>

🔬This is a nightly-only experimental API. (btree_cursors)

Available on crate feature alloc only.

Returns a reference to the key and value of the previous element without moving the cursor.

If the cursor is at the start of the map then None is returned.

Trait Implementations

impl<K, V> Clone for Cursor<'_, K, V>

fn clone(&self) -> Cursor<'_, K, V>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<K, V> Debug for Cursor<'_, K, V>

where K: Debug, V: Debug,

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.