Swift, Collection

1. Create a collection (unordered and non-repeatable)

(1) Create an empty collection

var a=set<int> ()//[]

(2) Create a collection

var a:set=[1,2,3]//[2,3,1]

2. Insert in the middle of the collection

var A:set=[1,2,3]a.insert (4)//[2,4,3,1]

3, set (remove) Delete

var a:set=[1,2,3]a.remove (2)//[3,1]

4. Whether the set (contains) has this element

var a:set=[1,2,3]print (A.contains (2))//true

5. Set conversion (sorted) to an array

var a:set=[1,2,3]var b=a.sorted ()//[1,2,3]

6. Special application of Set, subset, parent set, intersection, set, complement, difference set

(1) Intersection

Let X:set=[1,2,3]let y:set=[3,4,5]let z=x.intersection (y)//[3]

(2) Difference set

var x:set=[1,2,3]var y:set=[3,4,5]x.subtract (y)    //modify itself x,[2,1]

(3) and set

var x:set=[1,2,3]var y:set=[3,4,5]var z=x.union (y)//[3,4,1,5,2]

(4) Complementary set

var x:set=[1,2,3]var y:set=[3,4,5]var z=x.symmetricdifference (y)    //[5,2,4,1]

(5) determining whether a subset

var x:set=[3,4,5]var y:set=[3,4,5]var Z=x.issubset (of:y)//x is not a subset of Y, Truevar q=x.isstrictsubset (of:y)//strict subset, False

(6) Determine if the parent set

var x:set=[3,4,5]var y:set=[3,4,5]var Z=x.issuperset (of:y)//x is not a parent set of Y, Truevar q=x.isstrictsuperset (of:y)//strict parent set, False

(7) Determine if there is an intersection

var x:set=[3]var y:set=[3,4,5]var z=x.isdisjoint (with:y)//false

　　

　　

　　

Swift, Collection