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doc: TreeMap methods with examples.
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Small corrections for TreeSet examples.
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@treeman
treeman committed Jul 27, 2014
1 parent 034ef07 commit 8c34a97
Showing 1 changed file with 248 additions and 17 deletions.
265 changes: 248 additions & 17 deletions src/libcollections/treemap.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -43,10 +43,10 @@ use std::hash::{Writer, Hash};
use {Collection, Mutable, Set, MutableSet, MutableMap, Map, MutableSeq};
use vec::Vec;

// This is implemented as an AA tree, which is a simplified variation of
// a red-black tree where red (horizontal) nodes can only be added
// as a right child. The time complexity is the same, and re-balancing
// operations are more frequent but also cheaper.
/// This is implemented as an AA tree, which is a simplified variation of
/// a red-black tree where red (horizontal) nodes can only be added
/// as a right child. The time complexity is the same, and re-balancing
/// operations are more frequent but also cheaper.

// Future improvements:

Expand All @@ -59,7 +59,6 @@ use vec::Vec;
// * union: |
// These would be convenient since the methods work like `each`

#[allow(missing_doc)]
#[deriving(Clone)]
pub struct TreeMap<K, V> {
root: Option<Box<TreeNode<K, V>>>,
Expand Down Expand Up @@ -139,20 +138,73 @@ impl<K: Ord, V> Default for TreeMap<K,V> {

impl<K: Ord, V> TreeMap<K, V> {
/// Create an empty `TreeMap`.
///
/// # Example
///
/// ```
/// use std::collections::TreeMap;
/// let mut map: TreeMap<&str, int> = TreeMap::new();
/// ```
pub fn new() -> TreeMap<K, V> { TreeMap{root: None, length: 0} }

/// Get a lazy iterator over the keys in the map.
/// Get a lazy iterator over the keys in the map, in ascending order.
///
/// # Example
///
/// ```
/// use std::collections::TreeMap;
/// let mut map = TreeMap::new();
/// map.insert("a", 1i);
/// map.insert("c", 3i);
/// map.insert("b", 2i);
///
/// // Print "a", "b", "c" in order.
/// for x in map.keys() {
/// println!("{}", x);
/// }
/// ```
pub fn keys<'a>(&'a self) -> Keys<'a, K, V> {
self.iter().map(|(k, _v)| k)
}

/// Get a lazy iterator over the values in the map.
/// Get a lazy iterator over the values in the map, in ascending order
/// with respect to the corresponding keys.
///
/// # Example
///
/// ```
/// use std::collections::TreeMap;
/// let mut map = TreeMap::new();
/// map.insert("a", 1i);
/// map.insert("c", 3i);
/// map.insert("b", 2i);
///
/// // Print 1, 2, 3 ordered by keys.
/// for x in map.values() {
/// println!("{}", x);
/// }
/// ```
pub fn values<'a>(&'a self) -> Values<'a, K, V> {
self.iter().map(|(_k, v)| v)
}

/// Get a lazy iterator over the key-value pairs in the map.
/// Get a lazy iterator over the key-value pairs in the map, in ascending order.
/// Requires that it be frozen (immutable).
///
/// # Example
///
/// ```
/// use std::collections::TreeMap;
/// let mut map = TreeMap::new();
/// map.insert("a", 1i);
/// map.insert("c", 3i);
/// map.insert("b", 2i);
///
/// // Print contents in ascending order
/// for (key, value) in map.iter() {
/// println!("{}: {}", key, value);
/// }
/// ```
pub fn iter<'a>(&'a self) -> Entries<'a, K, V> {
Entries {
stack: vec!(),
Expand All @@ -162,14 +214,49 @@ impl<K: Ord, V> TreeMap<K, V> {
}
}

/// Get a lazy reverse iterator over the key-value pairs in the map.
/// Get a lazy reverse iterator over the key-value pairs in the map, in descending order.
/// Requires that it be frozen (immutable).
///
/// # Example
///
/// ```
/// use std::collections::TreeMap;
/// let mut map = TreeMap::new();
/// map.insert("a", 1i);
/// map.insert("c", 3i);
/// map.insert("b", 2i);
///
/// // Print contents in descending order
/// for (key, value) in map.rev_iter() {
/// println!("{}: {}", key, value);
/// }
/// ```
pub fn rev_iter<'a>(&'a self) -> RevEntries<'a, K, V> {
RevEntries{iter: self.iter()}
}

/// Get a lazy forward iterator over the key-value pairs in the
/// map, with the values being mutable.
///
/// # Example
///
/// ```
/// use std::collections::TreeMap;
/// let mut map = TreeMap::new();
/// map.insert("a", 1i);
/// map.insert("c", 3i);
/// map.insert("b", 2i);
///
/// // Add 10 until we find "b"
/// for (key, value) in map.mut_iter() {
/// *value += 10;
/// if key == &"b" { break }
/// }
///
/// assert_eq!(map.find(&"a"), Some(&11));
/// assert_eq!(map.find(&"b"), Some(&12));
/// assert_eq!(map.find(&"c"), Some(&3));
/// ```
pub fn mut_iter<'a>(&'a mut self) -> MutEntries<'a, K, V> {
MutEntries {
stack: vec!(),
Expand All @@ -180,12 +267,47 @@ impl<K: Ord, V> TreeMap<K, V> {
}
/// Get a lazy reverse iterator over the key-value pairs in the
/// map, with the values being mutable.
///
/// # Example
///
/// ```
/// use std::collections::TreeMap;
/// let mut map = TreeMap::new();
/// map.insert("a", 1i);
/// map.insert("c", 3i);
/// map.insert("b", 2i);
///
/// // Add 10 until we find "b"
/// for (key, value) in map.mut_rev_iter() {
/// *value += 10;
/// if key == &"b" { break }
/// }
///
/// assert_eq!(map.find(&"a"), Some(&1));
/// assert_eq!(map.find(&"b"), Some(&12));
/// assert_eq!(map.find(&"c"), Some(&13));
/// ```
pub fn mut_rev_iter<'a>(&'a mut self) -> RevMutEntries<'a, K, V> {
RevMutEntries{iter: self.mut_iter()}
}


/// Get a lazy iterator that consumes the treemap.
/// Get a lazy iterator that consumes the treemap, it is not usable
/// after calling this.
///
/// # Example
///
/// ```
/// use std::collections::TreeMap;
/// let mut map = TreeMap::new();
/// map.insert("a", 1i);
/// map.insert("c", 3i);
/// map.insert("b", 2i);
///
/// // Not possible with a regular `.iter()`
/// let vec: Vec<(&str, int)> = map.move_iter().collect();
/// assert_eq!(vec, vec![("a", 1), ("b", 2), ("c", 3)]);
/// ```
pub fn move_iter(self) -> MoveEntries<K, V> {
let TreeMap { root: root, length: length } = self;
let stk = match root {
Expand Down Expand Up @@ -302,12 +424,44 @@ impl<K: Ord, V> TreeMap<K, V> {

/// Return a lazy iterator to the first key-value pair whose key is not less than `k`
/// If all keys in map are less than `k` an empty iterator is returned.
///
/// # Example
///
/// ```
/// use std::collections::TreeMap;
///
/// let mut map = TreeMap::new();
/// map.insert(2i, "a");
/// map.insert(4, "b");
/// map.insert(6, "c");
/// map.insert(8, "d");
///
/// assert_eq!(map.lower_bound(&4).next(), Some((&4, &"b")));
/// assert_eq!(map.lower_bound(&5).next(), Some((&6, &"c")));
/// assert_eq!(map.lower_bound(&10).next(), None);
/// ```
pub fn lower_bound<'a>(&'a self, k: &K) -> Entries<'a, K, V> {
bound_setup!(self.iter_for_traversal(), k, true)
}

/// Return a lazy iterator to the first key-value pair whose key is greater than `k`
/// If all keys in map are not greater than `k` an empty iterator is returned.
/// If all keys in map are less than or equal to `k` an empty iterator is returned.
///
/// # Example
///
/// ```
/// use std::collections::TreeMap;
///
/// let mut map = TreeMap::new();
/// map.insert(2i, "a");
/// map.insert(4, "b");
/// map.insert(6, "c");
/// map.insert(8, "d");
///
/// assert_eq!(map.upper_bound(&4).next(), Some((&6, &"c")));
/// assert_eq!(map.upper_bound(&5).next(), Some((&6, &"c")));
/// assert_eq!(map.upper_bound(&10).next(), None);
/// ```
pub fn upper_bound<'a>(&'a self, k: &K) -> Entries<'a, K, V> {
bound_setup!(self.iter_for_traversal(), k, false)
}
Expand All @@ -328,15 +482,65 @@ impl<K: Ord, V> TreeMap<K, V> {
///
/// If all keys in map are less than `k` an empty iterator is
/// returned.
///
/// # Example
///
/// ```
/// use std::collections::TreeMap;
///
/// let mut map = TreeMap::new();
/// map.insert(2i, "a");
/// map.insert(4, "b");
/// map.insert(6, "c");
/// map.insert(8, "d");
///
/// assert_eq!(map.mut_lower_bound(&4).next(), Some((&4, &mut "b")));
/// assert_eq!(map.mut_lower_bound(&5).next(), Some((&6, &mut "c")));
/// assert_eq!(map.mut_lower_bound(&10).next(), None);
///
/// for (key, value) in map.mut_lower_bound(&4) {
/// *value = "changed";
/// }
///
/// assert_eq!(map.find(&2), Some(&"a"));
/// assert_eq!(map.find(&4), Some(&"changed"));
/// assert_eq!(map.find(&6), Some(&"changed"));
/// assert_eq!(map.find(&8), Some(&"changed"));
/// ```
pub fn mut_lower_bound<'a>(&'a mut self, k: &K) -> MutEntries<'a, K, V> {
bound_setup!(self.mut_iter_for_traversal(), k, true)
}

/// Return a lazy iterator to the first key-value pair (with the
/// value being mutable) whose key is greater than `k`.
///
/// If all keys in map are not greater than `k` an empty iterator
/// If all keys in map are less than or equal to `k` an empty iterator
/// is returned.
///
/// # Example
///
/// ```
/// use std::collections::TreeMap;
///
/// let mut map = TreeMap::new();
/// map.insert(2i, "a");
/// map.insert(4, "b");
/// map.insert(6, "c");
/// map.insert(8, "d");
///
/// assert_eq!(map.mut_upper_bound(&4).next(), Some((&6, &mut "c")));
/// assert_eq!(map.mut_upper_bound(&5).next(), Some((&6, &mut "c")));
/// assert_eq!(map.mut_upper_bound(&10).next(), None);
///
/// for (key, value) in map.mut_upper_bound(&4) {
/// *value = "changed";
/// }
///
/// assert_eq!(map.find(&2), Some(&"a"));
/// assert_eq!(map.find(&4), Some(&"b"));
/// assert_eq!(map.find(&6), Some(&"changed"));
/// assert_eq!(map.find(&8), Some(&"changed"));
/// ```
pub fn mut_upper_bound<'a>(&'a mut self, k: &K) -> MutEntries<'a, K, V> {
bound_setup!(self.mut_iter_for_traversal(), k, false)
}
Expand Down Expand Up @@ -853,13 +1057,36 @@ impl<T: Ord> TreeSet<T> {

/// Get a lazy iterator pointing to the first value not less than `v` (greater or equal).
/// If all elements in the set are less than `v` empty iterator is returned.
///
/// # Example
///
/// ```
/// use std::collections::TreeSet;
/// let set: TreeSet<int> = [2, 4, 6, 8].iter().map(|&x| x).collect();
///
/// assert_eq!(set.lower_bound(&4).next(), Some(&4));
/// assert_eq!(set.lower_bound(&5).next(), Some(&6));
/// assert_eq!(set.lower_bound(&10).next(), None);
/// ```
#[inline]
pub fn lower_bound<'a>(&'a self, v: &T) -> SetItems<'a, T> {
SetItems{iter: self.map.lower_bound(v)}
}

/// Get a lazy iterator pointing to the first value greater than `v`.
/// If all elements in the set are not greater than `v` empty iterator is returned.
/// If all elements in the set are less than or equal to `v` an
/// empty iterator is returned.
///
/// # Example
///
/// ```
/// use std::collections::TreeSet;
/// let set: TreeSet<int> = [2, 4, 6, 8].iter().map(|&x| x).collect();
///
/// assert_eq!(set.upper_bound(&4).next(), Some(&6));
/// assert_eq!(set.upper_bound(&5).next(), Some(&6));
/// assert_eq!(set.upper_bound(&10).next(), None);
/// ```
#[inline]
pub fn upper_bound<'a>(&'a self, v: &T) -> SetItems<'a, T> {
SetItems{iter: self.map.upper_bound(v)}
Expand All @@ -871,6 +1098,7 @@ impl<T: Ord> TreeSet<T> {
///
/// ```
/// use std::collections::TreeSet;
///
/// let a: TreeSet<int> = [1, 2, 3].iter().map(|&x| x).collect();
/// let b: TreeSet<int> = [3, 4, 5].iter().map(|&x| x).collect();
///
Expand All @@ -897,6 +1125,7 @@ impl<T: Ord> TreeSet<T> {
///
/// ```
/// use std::collections::TreeSet;
///
/// let a: TreeSet<int> = [1, 2, 3].iter().map(|&x| x).collect();
/// let b: TreeSet<int> = [3, 4, 5].iter().map(|&x| x).collect();
///
Expand All @@ -922,6 +1151,7 @@ impl<T: Ord> TreeSet<T> {
///
/// ```
/// use std::collections::TreeSet;
///
/// let a: TreeSet<int> = [1, 2, 3].iter().map(|&x| x).collect();
/// let b: TreeSet<int> = [2, 3, 4].iter().map(|&x| x).collect();
///
Expand All @@ -943,16 +1173,17 @@ impl<T: Ord> TreeSet<T> {
/// # Example
///
/// ```
/// use std::collections::HashSet;
/// let a: HashSet<int> = [1, 2, 3].iter().map(|&x| x).collect();
/// let b: HashSet<int> = [3, 4, 5].iter().map(|&x| x).collect();
/// use std::collections::TreeSet;
///
/// let a: TreeSet<int> = [1, 2, 3].iter().map(|&x| x).collect();
/// let b: TreeSet<int> = [3, 4, 5].iter().map(|&x| x).collect();
///
/// // Print 1, 2, 3, 4, 5 in ascending order.
/// for x in a.union(&b) {
/// println!("{}", x);
/// }
///
/// let diff: HashSet<int> = a.union(&b).map(|&x| x).collect();
/// let diff: TreeSet<int> = a.union(&b).map(|&x| x).collect();
/// assert_eq!(diff, [1, 2, 3, 4, 5].iter().map(|&x| x).collect());
/// ```
pub fn union<'a>(&'a self, other: &'a TreeSet<T>) -> UnionItems<'a, T> {
Expand Down

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