A preliminary knowledge of objective-c collection

Nsarray ordered Natural order

Nsset disorderly.

Nsset cannot store duplicate data, it can be used to remove duplicate data

1. Create a Collection

1.1 Creating immutable Collections

 
 
1     NSSet * set = [[NSSet alloc] initWithObjects:@"one",@"two",@"three", nil];
2     NSLog(@"%@",set);
3     
4     NSSet * set1 = [[NSSet alloc] initWithObjects:@"one",@"two",@"one",@"three", nil];
5     NSLog(@"%@",set1);

1.2 Creating a Mutable collection

 
1         NSMutableSet * muset = [[NSMutableSet alloc] initWithObjects:@"one",@"two", nil];
2         
3         NSLog(@"%@",muset);

2. Get the number of elements

1 nsuinteger count = [Set1 count]; 2 NSLog (@ "%lu", count);

3. Determine if the object is included

1 BOOL isContain = [set1 containsObject: @ "T"];
2 if (isContain) {
3 NSLog (@ "include");
4} else {
5 NSLog (@ "excluding");
6}

-(BOOL) Containsobject: (ObjectType) AnObject;

4. Array conversion to Collection

 
 
1     NSArray * arr = @[@"one",@"two",@"three",@"one"];
2     NSSet * set2 =[NSSet setWithArray:arr];
3     NSLog(@"set2 %@",set2);

5. Variable array additions and deletions

5.1 Add

1 [muset addobject:@ "three"]; 2 NSLog (@ "%@", muset);

5.2 Delete

1 [muset removeobject:@ "one"]; 2 NSLog (@ "%@", muset);

Delete all

1 [Muset removeallobjects]; 2 NSLog (@ "%@", muset);

A preliminary knowledge of objective-c collection