Struct indexmap::set::IndexSet [] [src]

pub struct IndexSet<T, S = RandomState> { /* fields omitted */ }

A hash set where the iteration order of the values is independent of their hash values.

The interface is closely compatible with the standard HashSet, but also has additional features.

Order

The values have a consistent order that is determined by the sequence of insertion and removal calls on the set. The order does not depend on the values or the hash function at all. Note that insertion order and value are not affected if a re-insertion is attempted once an element is already present.

All iterators traverse the set in order. Set operation iterators like union produce a concatenated order, as do their matching "bitwise" operators. See their documentation for specifics.

The insertion order is preserved, with notable exceptions like the .remove() or .swap_remove() methods. Methods such as .sort_by() of course result in a new order, depending on the sorting order.

Indices

The values are indexed in a compact range without holes in the range 0..self.len(). For example, the method .get_full looks up the index for a value, and the method .get_index looks up the value by index.

Examples

use indexmap::IndexSet;

// Collects which letters appear in a sentence.
let letters: IndexSet<_> = "a short treatise on fungi".chars().collect();
 
assert!(letters.contains(&'s'));
assert!(letters.contains(&'t'));
assert!(letters.contains(&'u'));
assert!(!letters.contains(&'y'));

Methods

impl<T> IndexSet<T>
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Create a new set. (Does not allocate.)

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Create a new set with capacity for n elements. (Does not allocate if n is zero.)

Computes in O(n) time.

impl<T, S> IndexSet<T, S>
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Create a new set with capacity for n elements. (Does not allocate if n is zero.)

Computes in O(n) time.

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Return the number of elements in the set.

Computes in O(1) time.

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Returns true if the set contains no elements.

Computes in O(1) time.

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Create a new set with hash_builder

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Return a reference to the set's BuildHasher.

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Computes in O(1) time.

impl<T, S> IndexSet<T, S> where
    T: Hash + Eq,
    S: BuildHasher
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Remove all elements in the set, while preserving its capacity.

Computes in O(n) time.

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FIXME Not implemented fully yet

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Insert the value into the set.

If an equivalent item already exists in the set, it returns false leaving the original value in the set and without altering its insertion order. Otherwise, it inserts the new item and returns true.

Computes in O(1) time (amortized average).

Important traits for Iter<'a, T>
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Return an iterator over the values of the set, in their order

Important traits for Difference<'a, T, S>
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Return an iterator over the values that are in self but not other.

Values are produced in the same order that they appear in self.

Important traits for SymmetricDifference<'a, T, S1, S2>
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Return an iterator over the values that are in self or other, but not in both.

Values from self are produced in their original order, followed by values from other in their original order.

Important traits for Intersection<'a, T, S>
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Return an iterator over the values that are in both self and other.

Values are produced in the same order that they appear in self.

Important traits for Union<'a, T, S>
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Return an iterator over all values that are in self or other.

Values from self are produced in their original order, followed by values that are unique to other in their original order.

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Return true if an equivalent to value exists in the set.

Computes in O(1) time (average).

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Return a reference to the value stored in the set, if it is present, else None.

Computes in O(1) time (average).

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Return item index and value

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Adds a value to the set, replacing the existing value, if any, that is equal to the given one. Returns the replaced value.

Computes in O(1) time (average).

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FIXME Same as .swap_remove

Computes in O(1) time (average).

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Remove the value from the set, and return true if it was present.

Like Vec::swap_remove, the value is removed by swapping it with the last element of the set and popping it off. This perturbs the postion of what used to be the last element!

Return false if value was not in the set.

Computes in O(1) time (average).

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FIXME Same as .swap_take

Computes in O(1) time (average).

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Removes and returns the value in the set, if any, that is equal to the given one.

Like Vec::swap_remove, the value is removed by swapping it with the last element of the set and popping it off. This perturbs the postion of what used to be the last element!

Return None if value was not in the set.

Computes in O(1) time (average).

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Remove the value from the set return it and the index it had.

Like Vec::swap_remove, the value is removed by swapping it with the last element of the set and popping it off. This perturbs the postion of what used to be the last element!

Return None if value was not in the set.

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Remove the last value

Computes in O(1) time (average).

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Scan through each value in the set and keep those where the closure keep returns true.

The elements are visited in order, and remaining elements keep their order.

Computes in O(n) time (average).

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Sort the set’s values by their default ordering.

See sort_by for details.

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Sort the set’s values in place using the comparison function compare.

Computes in O(n log n) time and O(n) space. The sort is stable.

Important traits for IntoIter<T>
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Sort the values of the set and return a by value iterator of the values with the result.

The sort is stable.

Important traits for Drain<'a, T>
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Clears the IndexSet, returning all values as a drain iterator. Keeps the allocated memory for reuse.

impl<T, S> IndexSet<T, S>
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Get a value by index

Valid indices are 0 <= index < self.len()

Computes in O(1) time.

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Remove the key-value pair by index

Valid indices are 0 <= index < self.len()

Computes in O(1) time (average).

impl<T, S> IndexSet<T, S> where
    T: Eq + Hash,
    S: BuildHasher
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Returns true if self has no elements in common with other.

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Returns true if all elements of self are contained in other.

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Returns true if all elements of other are contained in self.

Trait Implementations

impl<T: Clone, S: Clone> Clone for IndexSet<T, S>
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Returns a copy of the value. Read more

1.0.0
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Performs copy-assignment from source. Read more

impl<T, S> Debug for IndexSet<T, S> where
    T: Debug + Hash + Eq,
    S: BuildHasher
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Formats the value using the given formatter. Read more

impl<'a, T, S> IntoIterator for &'a IndexSet<T, S> where
    T: Hash + Eq,
    S: BuildHasher
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The type of the elements being iterated over.

Which kind of iterator are we turning this into?

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Creates an iterator from a value. Read more

impl<T, S> IntoIterator for IndexSet<T, S> where
    T: Hash + Eq,
    S: BuildHasher
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The type of the elements being iterated over.

Which kind of iterator are we turning this into?

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Creates an iterator from a value. Read more

impl<T, S> FromIterator<T> for IndexSet<T, S> where
    T: Hash + Eq,
    S: BuildHasher + Default
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Creates a value from an iterator. Read more

impl<T, S> Extend<T> for IndexSet<T, S> where
    T: Hash + Eq,
    S: BuildHasher
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Extends a collection with the contents of an iterator. Read more

impl<'a, T, S> Extend<&'a T> for IndexSet<T, S> where
    T: Hash + Eq + Copy,
    S: BuildHasher
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Extends a collection with the contents of an iterator. Read more

impl<T, S> Default for IndexSet<T, S> where
    S: BuildHasher + Default
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Return an empty IndexSet

impl<T, S1, S2> PartialEq<IndexSet<T, S2>> for IndexSet<T, S1> where
    T: Hash + Eq,
    S1: BuildHasher,
    S2: BuildHasher
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This method tests for self and other values to be equal, and is used by ==. Read more

1.0.0
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This method tests for !=.

impl<T, S> Eq for IndexSet<T, S> where
    T: Eq + Hash,
    S: BuildHasher
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impl<'a, 'b, T, S1, S2> BitAnd<&'b IndexSet<T, S2>> for &'a IndexSet<T, S1> where
    T: Eq + Hash + Clone,
    S1: BuildHasher + Default,
    S2: BuildHasher
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The resulting type after applying the & operator.

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Returns the set intersection, cloned into a new set.

Values are collected in the same order that they appear in self.

impl<'a, 'b, T, S1, S2> BitOr<&'b IndexSet<T, S2>> for &'a IndexSet<T, S1> where
    T: Eq + Hash + Clone,
    S1: BuildHasher + Default,
    S2: BuildHasher
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The resulting type after applying the | operator.

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Returns the set union, cloned into a new set.

Values from self are collected in their original order, followed by values that are unique to other in their original order.

impl<'a, 'b, T, S1, S2> BitXor<&'b IndexSet<T, S2>> for &'a IndexSet<T, S1> where
    T: Eq + Hash + Clone,
    S1: BuildHasher + Default,
    S2: BuildHasher
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The resulting type after applying the ^ operator.

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Returns the set symmetric-difference, cloned into a new set.

Values from self are collected in their original order, followed by values from other in their original order.

impl<'a, 'b, T, S1, S2> Sub<&'b IndexSet<T, S2>> for &'a IndexSet<T, S1> where
    T: Eq + Hash + Clone,
    S1: BuildHasher + Default,
    S2: BuildHasher
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The resulting type after applying the - operator.

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Returns the set difference, cloned into a new set.

Values are collected in the same order that they appear in self.