Struct indexmap::set::IndexSet [−][src]
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'));
Implementations
impl<T> IndexSet<T>
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pub fn new() -> Self
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Create a new set. (Does not allocate.)
pub fn with_capacity(n: usize) -> Self
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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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pub fn with_capacity_and_hasher(n: usize, hash_builder: S) -> Self
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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.
pub fn with_hasher(hash_builder: S) -> Self
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Create a new set with hash_builder
pub fn capacity(&self) -> usize
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Computes in O(1) time.
pub fn hasher(&self) -> &S
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Return a reference to the set’s BuildHasher
.
pub fn len(&self) -> usize
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Return the number of elements in the set.
Computes in O(1) time.
pub fn is_empty(&self) -> bool
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Returns true if the set contains no elements.
Computes in O(1) time.
pub fn iter(&self) -> Iter<'_, T>ⓘ
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Return an iterator over the values of the set, in their order
pub fn clear(&mut self)
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Remove all elements in the set, while preserving its capacity.
Computes in O(n) time.
pub fn truncate(&mut self, len: usize)
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Shortens the set, keeping the first len
elements and dropping the rest.
If len
is greater than the set’s current length, this has no effect.
pub fn drain<R>(&mut self, range: R) -> Drain<'_, T>ⓘ where
R: RangeBounds<usize>,
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R: RangeBounds<usize>,
Clears the IndexSet
in the given index range, returning those values
as a drain iterator.
The range may be any type that implements RangeBounds<usize>
,
including all of the std::ops::Range*
types, or even a tuple pair of
Bound
start and end values. To drain the set entirely, use RangeFull
like set.drain(..)
.
This shifts down all entries following the drained range to fill the gap, and keeps the allocated memory for reuse.
Panics if the starting point is greater than the end point or if the end point is greater than the length of the set.
pub fn split_off(&mut self, at: usize) -> Self where
S: Clone,
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S: Clone,
Splits the collection into two at the given index.
Returns a newly allocated set containing the elements in the range
[at, len)
. After the call, the original set will be left containing
the elements [0, at)
with its previous capacity unchanged.
Panics if at > len
.
impl<T, S> IndexSet<T, S> where
T: Hash + Eq,
S: BuildHasher,
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T: Hash + Eq,
S: BuildHasher,
pub fn reserve(&mut self, additional: usize)
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Reserve capacity for additional
more values.
Computes in O(n) time.
pub fn shrink_to_fit(&mut self)
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Shrink the capacity of the set as much as possible.
Computes in O(n) time.
pub fn insert(&mut self, value: T) -> bool
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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).
pub fn insert_full(&mut self, value: T) -> (usize, bool)
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Insert the value into the set, and get its index.
If an equivalent item already exists in the set, it returns
the index of the existing item and false
, leaving the
original value in the set and without altering its insertion
order. Otherwise, it inserts the new item and returns the index
of the inserted item and true
.
Computes in O(1) time (amortized average).
pub fn difference<'a, S2>(
&'a self,
other: &'a IndexSet<T, S2>
) -> Difference<'a, T, S2>ⓘNotable traits for Difference<'a, T, S>
impl<'a, T, S> Iterator for Difference<'a, T, S> where
T: Eq + Hash,
S: BuildHasher, type Item = &'a T;
where
S2: BuildHasher,
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&'a self,
other: &'a IndexSet<T, S2>
) -> Difference<'a, T, S2>ⓘ
Notable traits for Difference<'a, T, S>
impl<'a, T, S> Iterator for Difference<'a, T, S> where
T: Eq + Hash,
S: BuildHasher, type Item = &'a T;
S2: BuildHasher,
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
.
pub fn symmetric_difference<'a, S2>(
&'a self,
other: &'a IndexSet<T, S2>
) -> SymmetricDifference<'a, T, S, S2>ⓘNotable traits for SymmetricDifference<'a, T, S1, S2>
impl<'a, T, S1, S2> Iterator for SymmetricDifference<'a, T, S1, S2> where
T: Eq + Hash,
S1: BuildHasher,
S2: BuildHasher, type Item = &'a T;
where
S2: BuildHasher,
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&'a self,
other: &'a IndexSet<T, S2>
) -> SymmetricDifference<'a, T, S, S2>ⓘ
Notable traits for SymmetricDifference<'a, T, S1, S2>
impl<'a, T, S1, S2> Iterator for SymmetricDifference<'a, T, S1, S2> where
T: Eq + Hash,
S1: BuildHasher,
S2: BuildHasher, type Item = &'a T;
S2: BuildHasher,
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.
pub fn intersection<'a, S2>(
&'a self,
other: &'a IndexSet<T, S2>
) -> Intersection<'a, T, S2>ⓘNotable traits for Intersection<'a, T, S>
impl<'a, T, S> Iterator for Intersection<'a, T, S> where
T: Eq + Hash,
S: BuildHasher, type Item = &'a T;
where
S2: BuildHasher,
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&'a self,
other: &'a IndexSet<T, S2>
) -> Intersection<'a, T, S2>ⓘ
Notable traits for Intersection<'a, T, S>
impl<'a, T, S> Iterator for Intersection<'a, T, S> where
T: Eq + Hash,
S: BuildHasher, type Item = &'a T;
S2: BuildHasher,
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
.
pub fn union<'a, S2>(&'a self, other: &'a IndexSet<T, S2>) -> Union<'a, T, S>ⓘ where
S2: BuildHasher,
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S2: BuildHasher,
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.
pub fn contains<Q: ?Sized>(&self, value: &Q) -> bool where
Q: Hash + Equivalent<T>,
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Q: Hash + Equivalent<T>,
Return true
if an equivalent to value
exists in the set.
Computes in O(1) time (average).
pub fn get<Q: ?Sized>(&self, value: &Q) -> Option<&T> where
Q: Hash + Equivalent<T>,
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Q: Hash + Equivalent<T>,
Return a reference to the value stored in the set, if it is present,
else None
.
Computes in O(1) time (average).
pub fn get_full<Q: ?Sized>(&self, value: &Q) -> Option<(usize, &T)> where
Q: Hash + Equivalent<T>,
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Q: Hash + Equivalent<T>,
Return item index and value
pub fn get_index_of<Q: ?Sized>(&self, value: &Q) -> Option<usize> where
Q: Hash + Equivalent<T>,
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Q: Hash + Equivalent<T>,
Return item index, if it exists in the set
pub fn replace(&mut self, value: T) -> Option<T>
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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).
pub fn remove<Q: ?Sized>(&mut self, value: &Q) -> bool where
Q: Hash + Equivalent<T>,
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Q: Hash + Equivalent<T>,
Remove the value from the set, and return true
if it was present.
NOTE: This is equivalent to .swap_remove(value)
, if you want
to preserve the order of the values in the set, use .shift_remove(value)
.
Computes in O(1) time (average).
pub fn swap_remove<Q: ?Sized>(&mut self, value: &Q) -> bool where
Q: Hash + Equivalent<T>,
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Q: Hash + Equivalent<T>,
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 position of what used to be the last element!
Return false
if value
was not in the set.
Computes in O(1) time (average).
pub fn shift_remove<Q: ?Sized>(&mut self, value: &Q) -> bool where
Q: Hash + Equivalent<T>,
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Q: Hash + Equivalent<T>,
Remove the value from the set, and return true
if it was present.
Like Vec::remove
, the value is removed by shifting all of the
elements that follow it, preserving their relative order.
This perturbs the index of all of those elements!
Return false
if value
was not in the set.
Computes in O(n) time (average).
pub fn take<Q: ?Sized>(&mut self, value: &Q) -> Option<T> where
Q: Hash + Equivalent<T>,
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Q: Hash + Equivalent<T>,
Removes and returns the value in the set, if any, that is equal to the given one.
NOTE: This is equivalent to .swap_take(value)
, if you need to
preserve the order of the values in the set, use .shift_take(value)
instead.
Computes in O(1) time (average).
pub fn swap_take<Q: ?Sized>(&mut self, value: &Q) -> Option<T> where
Q: Hash + Equivalent<T>,
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Q: Hash + Equivalent<T>,
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 position of what used to be the last element!
Return None
if value
was not in the set.
Computes in O(1) time (average).
pub fn shift_take<Q: ?Sized>(&mut self, value: &Q) -> Option<T> where
Q: Hash + Equivalent<T>,
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Q: Hash + Equivalent<T>,
Removes and returns the value in the set, if any, that is equal to the given one.
Like Vec::remove
, the value is removed by shifting all of the
elements that follow it, preserving their relative order.
This perturbs the index of all of those elements!
Return None
if value
was not in the set.
Computes in O(n) time (average).
pub fn swap_remove_full<Q: ?Sized>(&mut self, value: &Q) -> Option<(usize, T)> where
Q: Hash + Equivalent<T>,
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Q: Hash + Equivalent<T>,
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 position of what used to be the last element!
Return None
if value
was not in the set.
pub fn shift_remove_full<Q: ?Sized>(&mut self, value: &Q) -> Option<(usize, T)> where
Q: Hash + Equivalent<T>,
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Q: Hash + Equivalent<T>,
Remove the value from the set return it and the index it had.
Like Vec::remove
, the value is removed by shifting all of the
elements that follow it, preserving their relative order.
This perturbs the index of all of those elements!
Return None
if value
was not in the set.
pub fn pop(&mut self) -> Option<T>
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Remove the last value
Computes in O(1) time (average).
pub fn retain<F>(&mut self, keep: F) where
F: FnMut(&T) -> bool,
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F: FnMut(&T) -> bool,
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).
pub fn sort(&mut self) where
T: Ord,
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T: Ord,
Sort the set’s values by their default ordering.
See sort_by
for details.
pub fn sort_by<F>(&mut self, compare: F) where
F: FnMut(&T, &T) -> Ordering,
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F: FnMut(&T, &T) -> Ordering,
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.
pub fn sorted_by<F>(self, cmp: F) -> IntoIter<T>ⓘ where
F: FnMut(&T, &T) -> Ordering,
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F: FnMut(&T, &T) -> Ordering,
Sort the values of the set and return a by value iterator of the values with the result.
The sort is stable.
pub fn reverse(&mut self)
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Reverses the order of the set’s values in place.
Computes in O(n) time and O(1) space.
impl<T, S> IndexSet<T, S>
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pub fn get_index(&self, index: usize) -> Option<&T>
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Get a value by index
Valid indices are 0 <= index < self.len()
Computes in O(1) time.
pub fn first(&self) -> Option<&T>
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Get the first value
Computes in O(1) time.
pub fn last(&self) -> Option<&T>
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Get the last value
Computes in O(1) time.
pub fn swap_remove_index(&mut self, index: usize) -> Option<T>
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Remove the value by index
Valid indices are 0 <= index < self.len()
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 position of what used to be the last element!
Computes in O(1) time (average).
pub fn shift_remove_index(&mut self, index: usize) -> Option<T>
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Remove the value by index
Valid indices are 0 <= index < self.len()
Like Vec::remove
, the value is removed by shifting all of the
elements that follow it, preserving their relative order.
This perturbs the index of all of those elements!
Computes in O(n) time (average).
pub fn swap_indices(&mut self, a: usize, b: usize)
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Swaps the position of two values in the set.
Panics if a
or b
are out of bounds.
impl<T, S> IndexSet<T, S> where
T: Eq + Hash,
S: BuildHasher,
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T: Eq + Hash,
S: BuildHasher,
pub fn is_disjoint<S2>(&self, other: &IndexSet<T, S2>) -> bool where
S2: BuildHasher,
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S2: BuildHasher,
Returns true
if self
has no elements in common with other
.
pub fn is_subset<S2>(&self, other: &IndexSet<T, S2>) -> bool where
S2: BuildHasher,
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S2: BuildHasher,
Returns true
if all elements of self
are contained in other
.
pub fn is_superset<S2>(&self, other: &IndexSet<T, S2>) -> bool where
S2: BuildHasher,
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S2: BuildHasher,
Returns true
if all elements of other
are contained in self
.
Trait Implementations
impl<T, S1, S2> BitAnd<&'_ IndexSet<T, S2>> for &IndexSet<T, S1> where
T: Eq + Hash + Clone,
S1: BuildHasher + Default,
S2: BuildHasher,
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T: Eq + Hash + Clone,
S1: BuildHasher + Default,
S2: BuildHasher,
type Output = IndexSet<T, S1>
The resulting type after applying the &
operator.
fn bitand(self, other: &IndexSet<T, S2>) -> Self::Output
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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<T, S1, S2> BitOr<&'_ IndexSet<T, S2>> for &IndexSet<T, S1> where
T: Eq + Hash + Clone,
S1: BuildHasher + Default,
S2: BuildHasher,
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T: Eq + Hash + Clone,
S1: BuildHasher + Default,
S2: BuildHasher,
type Output = IndexSet<T, S1>
The resulting type after applying the |
operator.
fn bitor(self, other: &IndexSet<T, S2>) -> Self::Output
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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<T, S1, S2> BitXor<&'_ IndexSet<T, S2>> for &IndexSet<T, S1> where
T: Eq + Hash + Clone,
S1: BuildHasher + Default,
S2: BuildHasher,
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T: Eq + Hash + Clone,
S1: BuildHasher + Default,
S2: BuildHasher,
type Output = IndexSet<T, S1>
The resulting type after applying the ^
operator.
fn bitxor(self, other: &IndexSet<T, S2>) -> Self::Output
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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<T, S> Clone for IndexSet<T, S> where
T: Clone,
S: Clone,
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T: Clone,
S: Clone,
fn clone(&self) -> Self
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fn clone_from(&mut self, other: &Self)
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impl<T, S> Debug for IndexSet<T, S> where
T: Debug,
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T: Debug,
impl<T, S> Default for IndexSet<T, S> where
S: Default,
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S: Default,
impl<T, S> Eq for IndexSet<T, S> where
T: Eq + Hash,
S: BuildHasher,
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T: Eq + Hash,
S: BuildHasher,
impl<'a, T, S> Extend<&'a T> for IndexSet<T, S> where
T: Hash + Eq + Copy + 'a,
S: BuildHasher,
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T: Hash + Eq + Copy + 'a,
S: BuildHasher,
fn extend<I: IntoIterator<Item = &'a T>>(&mut self, iterable: I)
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pub fn extend_one(&mut self, item: A)
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pub fn extend_reserve(&mut self, additional: usize)
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impl<T, S> Extend<T> for IndexSet<T, S> where
T: Hash + Eq,
S: BuildHasher,
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T: Hash + Eq,
S: BuildHasher,
fn extend<I: IntoIterator<Item = T>>(&mut self, iterable: I)
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pub fn extend_one(&mut self, item: A)
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pub fn extend_reserve(&mut self, additional: usize)
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impl<T, S> FromIterator<T> for IndexSet<T, S> where
T: Hash + Eq,
S: BuildHasher + Default,
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T: Hash + Eq,
S: BuildHasher + Default,
fn from_iter<I: IntoIterator<Item = T>>(iterable: I) -> Self
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impl<T, S> Index<usize> for IndexSet<T, S>
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Access IndexSet
values at indexed positions.
Examples
use indexmap::IndexSet; let mut set = IndexSet::new(); for word in "Lorem ipsum dolor sit amet".split_whitespace() { set.insert(word.to_string()); } assert_eq!(set[0], "Lorem"); assert_eq!(set[1], "ipsum"); set.reverse(); assert_eq!(set[0], "amet"); assert_eq!(set[1], "sit"); set.sort(); assert_eq!(set[0], "Lorem"); assert_eq!(set[1], "amet");
use indexmap::IndexSet; let mut set = IndexSet::new(); set.insert("foo"); println!("{:?}", set[10]); // panics!
type Output = T
The returned type after indexing.
fn index(&self, index: usize) -> &T
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Returns a reference to the value at the supplied index
.
Panics if index
is out of bounds.
impl<'a, T, S> IntoIterator for &'a IndexSet<T, S>
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type Item = &'a T
The type of the elements being iterated over.
type IntoIter = Iter<'a, T>
Which kind of iterator are we turning this into?
fn into_iter(self) -> Self::IntoIter
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impl<T, S> IntoIterator for IndexSet<T, S>
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type Item = T
The type of the elements being iterated over.
type IntoIter = IntoIter<T>
Which kind of iterator are we turning this into?
fn into_iter(self) -> Self::IntoIter
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impl<T, S1, S2> PartialEq<IndexSet<T, S2>> for IndexSet<T, S1> where
T: Hash + Eq,
S1: BuildHasher,
S2: BuildHasher,
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T: Hash + Eq,
S1: BuildHasher,
S2: BuildHasher,
fn eq(&self, other: &IndexSet<T, S2>) -> bool
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#[must_use]pub fn ne(&self, other: &Rhs) -> bool
1.0.0[src]
impl<T, S1, S2> Sub<&'_ IndexSet<T, S2>> for &IndexSet<T, S1> where
T: Eq + Hash + Clone,
S1: BuildHasher + Default,
S2: BuildHasher,
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T: Eq + Hash + Clone,
S1: BuildHasher + Default,
S2: BuildHasher,
Auto Trait Implementations
impl<T, S> RefUnwindSafe for IndexSet<T, S> where
S: RefUnwindSafe,
T: RefUnwindSafe,
S: RefUnwindSafe,
T: RefUnwindSafe,
impl<T, S> Send for IndexSet<T, S> where
S: Send,
T: Send,
S: Send,
T: Send,
impl<T, S> Sync for IndexSet<T, S> where
S: Sync,
T: Sync,
S: Sync,
T: Sync,
impl<T, S> Unpin for IndexSet<T, S> where
S: Unpin,
T: Unpin,
S: Unpin,
T: Unpin,
impl<T, S> UnwindSafe for IndexSet<T, S> where
S: UnwindSafe,
T: UnwindSafe,
S: UnwindSafe,
T: UnwindSafe,
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut T
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impl<T> From<T> for T
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
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pub fn clone_into(&self, target: &mut T)
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,