lyng/docs/Set.md

List built-in class

Mutable set of any objects: a group of different objects, no repetitions. Sets are not ordered, order of appearance does not matter.

val set = Set(1,2,3, "foo")
assert( 1 in set )
assert( "foo" in set)
assert( "bar" !in set)
>>> void

Set is collection and therefore [Iterable]:

assert( Set(1,2) is Set)
assert( Set(1,2) is Iterable)
assert( Set(1,2) is Collection)
>>> void

So it supports all methods from [Iterable]; set is not, though, an [Array] and has no indexing. Use [set.toList] as needed.

Set operations

// Union
assertEquals( Set(1,2,3,4), Set(3, 1) + Set(2, 4))

// intersection
assertEquals( Set(1,4), Set(3, 1, 4).intersect(Set(2, 4, 1)) )
// or simple
assertEquals( Set(1,4), Set(3, 1, 4) * Set(2, 4, 1) )

// To find collection elements not present in another collection, use the 
// subtract() or `-`:
assertEquals( Set( 1, 2), Set(1, 2, 4, 3) - Set(3, 4))

>>> void

Adding elements

var s = Set()
s += 1
assertEquals( Set(1), s)

s += [3, 3, 4]
assertEquals( Set(3, 4, 1), s)
>>> void

Removing elements

List is mutable, so it is possible to remove its contents. To remove a single element by index use:

var s = Set(1,2,3)
s.remove(2)
assertEquals( s, Set(1,3) )

s = Set(1,2,3)
s.remove(2,1)
assertEquals( s, Set(3) )
>>> void

Note that remove returns true if at least one element was actually removed and false if the set has not been changed.

Comparisons and inclusion

Sets are only equal when contains exactly same elements, order, as was said, is not significant:

assert( Set(1, 2) == Set(2, 1) )
assert( Set(1, 2, 2) == Set(2, 1) )
assert( Set(1, 3) != Set(2, 1) )
assert( 1 in Set(5,1))
assert( 10 !in Set(5,1))
>>> void

Members

name	meaning	type
size	current size	Int
+=	add one or more elements	Any
+, union	union sets	Any
-, subtract	subtract sets	Any
*, intersect	subtract sets	Any
remove(items...)	remove one or more items	Range
contains(element)	check the element is in the list (1)

(1)

optimized implementation that override Iterable one

Also, it inherits methods from [Iterable].