如何在目标c中执行移位和推动操作

Question

I have an array [1,2,3,4]

I need to continously shift and push one element into the same array

so that the first variable values will be 1,2,3,4,1,2,3,4,...

and second variable values will be 2,3,4,1,2,3,4,1,...

How to do that??

Answer 1

Use NSMutableArray like:

1) to get the object at the first position:

object = [nameArray firstObject];
[nameArray removeObjectAtIndex:0];

2) then insert it in last position:

[nameArray addObject:object];

ps remember to always add some sanity checks.

Answer 2

You would need

- exchangeObjectAtIndex:withObjectAtIndex:

Exchanges the objects in the array at given indices.

See Documentation here

Example

NSMutableArray *array = [NSMutableArray array];
    [array setArray:@[@"Eezy",@"Tutorials",@"Website"]];
    [array exchangeObjectAtIndex:0 withObjectAtIndex:2];
NSLog(@"%@",array); 

NSMutableArray *obj = [NSMutableArray arrayWithObjects:@"1",@"2",@"3",nil];
    [obj exchangeObjectAtIndex:0 withObjectAtIndex:obj.count - 1];

 NSLog(@"%@",obj);