A generic hash set.

Use init proc or initHashSet proc before calling other procs on it.

A generic hash set that remembers insertion order.

Use init proc or initOrderedSet proc before calling other procs on it.

Deprecated since Nim v1.4.0, it is not needed anymore because picking the correct size is done internally.

Return the value of initialSize to support count items.

If more items are expected to be added, simply add that expected extra amount to the parameter before calling this.

Initializes a hash set.

Starting from Nim v0.20, sets are initialized by default and it is not necessary to call this function explicitly.

You can call this proc on a previously initialized hash set, which will discard all its values. This might be more convenient than iterating over existing values and calling excl() on them.

See also:

• initHashSet proc
• toHashSet proc

Example:

var a: HashSet[int]
init(a)

Wrapper around init proc for initialization of hash sets.

Returns an empty hash set you can assign directly in var blocks in a single line.

Starting from Nim v0.20, sets are initialized by default and it is not necessary to call this function explicitly.

See also:

• toHashSet proc

Example:

var a = initHashSet[int]()
a.incl(3)
assert len(a) == 1

Returns the element that is actually stored in s which has the same value as key or raises the KeyError exception.

This is useful when one overloaded hash and == but still needs reference semantics for sharing.

Returns true if key is in s.

This allows the usage of in operator.

See also:

• incl proc
• containsOrIncl proc

Example:

var values = initHashSet[int]()
assert(not values.contains(2))
assert 2 notin values

values.incl(2)
assert values.contains(2)
assert 2 in values

Includes an element key in s.

This doesn't do anything if key is already in s.

See also:

• excl proc for excluding an element
• incl proc for including other set
• containsOrIncl proc

Example:

var values = initHashSet[int]()
values.incl(2)
values.incl(2)
assert values.len == 1

Includes all elements from other set into s (must be declared as var).

This is the in-place version of s + other.

See also:

• excl proc for excluding other set
• incl proc for including an element
• containsOrIncl proc

Example:

var
  values = toHashSet([1, 2, 3])
  others = toHashSet([3, 4, 5])
values.incl(others)
assert values.len == 5

Creates a new hash set that contains the members of the given collection (seq, array, or string) keys.

Duplicates are removed.

See also:

• initHashSet proc

Example:

let
  a = toHashSet([5, 3, 2])
  b = toHashSet("abracadabra")
assert len(a) == 3
## a == {2, 3, 5}
assert len(b) == 5
## b == {'a', 'b', 'c', 'd', 'r'}

Includes key in the set s and tells if key was already in s.

The difference with regards to the incl proc is that this proc returns true if s already contained key. The proc will return false if key was added as a new value to s during this call.

See also:

• incl proc for including an element
• incl proc for including other set
• missingOrExcl proc

Example:

var values = initHashSet[int]()
assert values.containsOrIncl(2) == false
assert values.containsOrIncl(2) == true
assert values.containsOrIncl(3) == false

Excludes key from the set s.

This doesn't do anything if key is not found in s.

See also:

• incl proc for including an element
• excl proc for excluding other set
• missingOrExcl proc

Example:

var s = toHashSet([2, 3, 6, 7])
s.excl(2)
s.excl(2)
assert s.len == 3

Excludes all elements of other set from s.

This is the in-place version of s - other.

See also:

• incl proc for including other set
• excl proc for excluding an element
• missingOrExcl proc

Example:

var
  numbers = toHashSet([1, 2, 3, 4, 5])
  even = toHashSet([2, 4, 6, 8])
numbers.excl(even)
assert len(numbers) == 3
## numbers == {1, 3, 5}

Excludes key in the set s and tells if key was already missing from s.

The difference with regards to the excl proc is that this proc returns true if key was missing from s. The proc will return false if key was in s and it was removed during this call.

See also:

• excl proc for excluding an element
• excl proc for excluding other set
• containsOrIncl proc

Example:

var s = toHashSet([2, 3, 6, 7])
assert s.missingOrExcl(4) == true
assert s.missingOrExcl(6) == false
assert s.missingOrExcl(6) == true

Removes and returns an arbitrary element from the set s.

Raises KeyError if the set s is empty.

See also:

• clear proc

Example:

var s = toHashSet([2, 1])
assert [s.pop, s.pop] in [[1, 2], [2,1]] # order unspecified
doAssertRaises(KeyError, echo s.pop)

Clears the HashSet back to an empty state, without shrinking any of the existing storage.

O(n) operation, where n is the size of the hash bucket.

See also:

• pop proc

Example:

var s = toHashSet([3, 5, 7])
clear(s)
assert len(s) == 0

Returns the number of elements in s.

Due to an implementation detail you can call this proc on variables which have not been initialized yet. The proc will return zero as the length then.

Example:

var a: HashSet[string]
assert len(a) == 0
let s = toHashSet([3, 5, 7])
assert len(s) == 3

Alias for len().

Card stands for the cardinality of a set.

Returns the union of the sets s1 and s2.

The same as s1 + s2.

The union of two sets is represented mathematically as A ∪ B and is the set of all objects that are members of s1, s2 or both.

See also:

• intersection proc
• difference proc
• symmetricDifference proc

Example:

let
  a = toHashSet(["a", "b"])
  b = toHashSet(["b", "c"])
  c = union(a, b)
assert c == toHashSet(["a", "b", "c"])

Returns the intersection of the sets s1 and s2.

The same as s1 * s2.

The intersection of two sets is represented mathematically as A ∩ B and is the set of all objects that are members of s1 and s2 at the same time.

See also:

• union proc
• difference proc
• symmetricDifference proc

Example:

let
  a = toHashSet(["a", "b"])
  b = toHashSet(["b", "c"])
  c = intersection(a, b)
assert c == toHashSet(["b"])

Returns the difference of the sets s1 and s2.

The same as s1 - s2.

The difference of two sets is represented mathematically as A ∖ B and is the set of all objects that are members of s1 and not members of s2.

See also:

• union proc
• intersection proc
• symmetricDifference proc

Example:

let
  a = toHashSet(["a", "b"])
  b = toHashSet(["b", "c"])
  c = difference(a, b)
assert c == toHashSet(["a"])

Returns the symmetric difference of the sets s1 and s2.

The same as s1 -+- s2.

The symmetric difference of two sets is represented mathematically as A △ B or A ⊖ B and is the set of all objects that are members of s1 or s2 but not both at the same time.

See also:

• union proc
• intersection proc
• difference proc

Example:

let
  a = toHashSet(["a", "b"])
  b = toHashSet(["b", "c"])
  c = symmetricDifference(a, b)
assert c == toHashSet(["a", "c"])

Example:

let
  a = toHashSet(["a", "b"])
  b = toHashSet(["b", "c"])
assert disjoint(a, b) == false
assert disjoint(a, b - a) == true

Returns true if s is a strict or proper subset of t.

A strict or proper subset s has all of its members in t but t has more elements than s.

Example:

let
  a = toHashSet(["a", "b"])
  b = toHashSet(["b", "c"])
  c = intersection(a, b)
assert c < a and c < b
assert(not (a < a))

Returns true if s is a subset of t.

A subset s has all of its members in t and t doesn't necessarily have more members than s. That is, s can be equal to t.

Example:

let
  a = toHashSet(["a", "b"])
  b = toHashSet(["b", "c"])
  c = intersection(a, b)
assert c <= a and c <= b
assert a <= a

Example:

var
  a = toHashSet([1, 2])
  b = toHashSet([2, 1])
assert a == b

Returns a new set after applying op proc on each of the elements of data set.

You can use this proc to transform the elements from a set.

Example:

let
  a = toHashSet([1, 2, 3])
  b = a.map(proc (x: int): string = $x)
assert b == toHashSet(["1", "2", "3"])

Converts the set s to a string, mostly for logging and printing purposes.

Don't use this proc for serialization, the representation may change at any moment and values are not escaped.

Examples:

echo toHashSet([2, 4, 5])
# --> {2, 4, 5}
echo toHashSet(["no", "esc'aping", "is \" provided"])
# --> {no, esc'aping, is " provided}

Returns true if the set has been initialized (with initHashSet proc or init proc).

Examples:

proc savePreferences(options: HashSet[string]) =
  assert options.isValid, "Pass an initialized set!"
  # Do stuff here, may crash in release builds!

Initializes an ordered hash set.

Starting from Nim v0.20, sets are initialized by default and it is not necessary to call this function explicitly.

You can call this proc on a previously initialized hash set, which will discard all its values. This might be more convenient than iterating over existing values and calling excl() on them.

See also:

• initOrderedSet proc
• toOrderedSet proc

Example:

var a: OrderedSet[int]
init(a)

Wrapper around init proc for initialization of ordered hash sets.

Returns an empty ordered hash set you can assign directly in var blocks in a single line.

Starting from Nim v0.20, sets are initialized by default and it is not necessary to call this function explicitly.

See also:

• toOrderedSet proc

Example:

var a = initOrderedSet[int]()
a.incl(3)
assert len(a) == 1

Creates a new hash set that contains the members of the given collection (seq, array, or string) keys.

Duplicates are removed.

See also:

• initOrderedSet proc

Example:

let
  a = toOrderedSet([5, 3, 2])
  b = toOrderedSet("abracadabra")
assert len(a) == 3
## a == {5, 3, 2} # different than in HashSet
assert len(b) == 5
## b == {'a', 'b', 'r', 'c', 'd'} # different than in HashSet

Returns true if key is in s.

This allows the usage of in operator.

See also:

• incl proc
• containsOrIncl proc

Example:

var values = initOrderedSet[int]()
assert(not values.contains(2))
assert 2 notin values

values.incl(2)
assert values.contains(2)
assert 2 in values

Includes an element key in s.

This doesn't do anything if key is already in s.

See also:

• excl proc for excluding an element
• incl proc for including other set
• containsOrIncl proc

Example:

var values = initOrderedSet[int]()
values.incl(2)
values.incl(2)
assert values.len == 1

Includes all elements from the OrderedSet other into HashSet s (must be declared as var).

See also:

• incl proc for including an element
• containsOrIncl proc

Example:

var
  values = toHashSet([1, 2, 3])
  others = toOrderedSet([3, 4, 5])
values.incl(others)
assert values.len == 5

Includes key in the set s and tells if key was already in s.

The difference with regards to the incl proc is that this proc returns true if s already contained key. The proc will return false if key was added as a new value to s during this call.

See also:

• incl proc for including an element
• missingOrExcl proc

Example:

var values = initOrderedSet[int]()
assert values.containsOrIncl(2) == false
assert values.containsOrIncl(2) == true
assert values.containsOrIncl(3) == false

Excludes key from the set s. Efficiency: O(n).

This doesn't do anything if key is not found in s.

See also:

• incl proc for including an element
• missingOrExcl proc

Example:

var s = toOrderedSet([2, 3, 6, 7])
s.excl(2)
s.excl(2)
assert s.len == 3

Excludes key in the set s and tells if key was already missing from s. Efficiency: O(n).

The difference with regards to the excl proc is that this proc returns true if key was missing from s. The proc will return false if key was in s and it was removed during this call.

See also:

• excl proc
• containsOrIncl proc

Example:

var s = toOrderedSet([2, 3, 6, 7])
assert s.missingOrExcl(4) == true
assert s.missingOrExcl(6) == false
assert s.missingOrExcl(6) == true

Clears the OrderedSet back to an empty state, without shrinking any of the existing storage.

O(n) operation where n is the size of the hash bucket.

Example:

var s = toOrderedSet([3, 5, 7])
clear(s)
assert len(s) == 0

Returns the number of elements in s.

Due to an implementation detail you can call this proc on variables which have not been initialized yet. The proc will return zero as the length then.

Example:

var a: OrderedSet[string]
assert len(a) == 0
let s = toHashSet([3, 5, 7])
assert len(s) == 3

Alias for len().

Card stands for the cardinality of a set.

Example:

let
  a = toOrderedSet([1, 2])
  b = toOrderedSet([2, 1])
assert(not (a == b))

Converts the ordered hash set s to a string, mostly for logging and printing purposes.

Don't use this proc for serialization, the representation may change at any moment and values are not escaped.

Examples:

echo toOrderedSet([2, 4, 5])
# --> {2, 4, 5}
echo toOrderedSet(["no", "esc'aping", "is \" provided"])
# --> {no, esc'aping, is " provided}

Iterates over elements of the set s.

If you need a sequence with the elements you can use sequtils.toSeq template.

type
  pair = tuple[a, b: int]
var
  a, b = initHashSet[pair]()
a.incl((2, 3))
a.incl((3, 2))
a.incl((2, 3))
for x, y in a.items:
  b.incl((x - 2, y + 1))
assert a.len == 2
echo b
# --> {(a: 1, b: 3), (a: 0, b: 4)}

Iterates over keys in the ordered set s in insertion order.

If you need a sequence with the elements you can use sequtils.toSeq template.

var a = initOrderedSet[int]()
for value in [9, 2, 1, 5, 1, 8, 4, 2]:
  a.incl(value)
for value in a.items:
  echo "Got ", value
# --> Got 9
# --> Got 2
# --> Got 1
# --> Got 5
# --> Got 8
# --> Got 4

Example:

let a = toOrderedSet("abracadabra")
var p = newSeq[(int, char)]()
for x in pairs(a):
  p.add(x)
assert p == @[(0, 'a'), (1, 'b'), (2, 'r'), (3, 'c'), (4, 'd')]