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Struct std::collections::btree_map::Cursor

pub struct Cursor<'a, K, V>
where
    K: 'a,
    V: 'a,{ /* private fields */ }
🔬This is a nightly-only experimental API. (btree_cursors #107540)

A cursor over a BTreeMap.

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

Cursors always point to an element in the tree, and index in a logically circular way. To accommodate this, there is a “ghost” non-element that yields None between the last and first elements of the tree.

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

Implementations

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impl<'a, K, V> Cursor<'a, K, V>
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pub fn move_next(&mut self)
🔬This is a nightly-only experimental API. (btree_cursors #107540)

Moves the cursor to the next element of the BTreeMap.

If the cursor is pointing to the “ghost” non-element then this will move it to the first element of the BTreeMap. If it is pointing to the last element of the BTreeMap then this will move it to the “ghost” non-element.

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pub fn move_prev(&mut self)
🔬This is a nightly-only experimental API. (btree_cursors #107540)

Moves the cursor to the previous element of the BTreeMap.

If the cursor is pointing to the “ghost” non-element then this will move it to the last element of the BTreeMap. If it is pointing to the first element of the BTreeMap then this will move it to the “ghost” non-element.

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pub fn key(&self) -> Option<&'a K>
🔬This is a nightly-only experimental API. (btree_cursors #107540)

Returns a reference to the key of the element that the cursor is currently pointing to.

This returns None if the cursor is currently pointing to the “ghost” non-element.

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pub fn value(&self) -> Option<&'a V>
🔬This is a nightly-only experimental API. (btree_cursors #107540)

Returns a reference to the value of the element that the cursor is currently pointing to.

This returns None if the cursor is currently pointing to the “ghost” non-element.

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pub fn key_value(&self) -> Option<(&'a K, &'a V)>
🔬This is a nightly-only experimental API. (btree_cursors #107540)

Returns a reference to the key and value of the element that the cursor is currently pointing to.

This returns None if the cursor is currently pointing to the “ghost” non-element.

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pub fn peek_next(&self) -> Option<(&'a K, &'a V)>
🔬This is a nightly-only experimental API. (btree_cursors #107540)

Returns a reference to the next element.

If the cursor is pointing to the “ghost” non-element then this returns the first element of the BTreeMap. If it is pointing to the last element of the BTreeMap then this returns None.

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pub fn peek_prev(&self) -> Option<(&'a K, &'a V)>
🔬This is a nightly-only experimental API. (btree_cursors #107540)

Returns a reference to the previous element.

If the cursor is pointing to the “ghost” non-element then this returns the last element of the BTreeMap. If it is pointing to the first element of the BTreeMap then this returns None.

Trait Implementations

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impl<K, V> Clone for Cursor<'_, K, V>
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fn clone(&self) -> Cursor<'_, K, V>
Returns a copy of the value. Read more
1.0.0source 
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
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impl<K, V> Debug for Cursor<'_, K, V>
where
    K: Debug,
    V: Debug,
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fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more

Auto Trait Implementations

impl<'a, K, V> RefUnwindSafe for Cursor<'a, K, V>
where
    K: RefUnwindSafe,
    V: RefUnwindSafe,
impl<'a, K, V> Send for Cursor<'a, K, V>
where
    K: Sync,
    V: Sync,
impl<'a, K, V> Sync for Cursor<'a, K, V>
where
    K: Sync,
    V: Sync,
impl<'a, K, V> Unpin for Cursor<'a, K, V>
impl<'a, K, V> UnwindSafe for Cursor<'a, K, V>
where
    K: RefUnwindSafe,
    V: RefUnwindSafe,

Blanket Implementations

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impl<T> Any for T
where
    T: 'static + ?Sized,
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fn type_id(&self) -> TypeId
Gets the TypeId of self. Read more
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impl<T> Borrow<T> for T
where
    T: ?Sized,
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fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where
    T: ?Sized,
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fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more
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impl<T> From<T> for T
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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where
    U: From<T>,
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fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for T
where
    T: Clone,
 
type Owned = T
The resulting type after obtaining ownership.
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fn to_owned(&self) -> T
Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)
Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for T
where
    U: Into<T>,
 
type Error = Infallible
The type returned in the event of a conversion error.
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fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
Performs the conversion.
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impl<T, U> TryInto<U> for T
where
    U: TryFrom<T>,
 
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
Performs the conversion.

© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/collections/btree_map/struct.Cursor.html