sh数组快速倒序    

 NSArray *arr = @[@"first",@"second"];

arr = arr.reverseObjectEnumerator.allObjects;

NSLog(@"%@",arr);

 

数组快速去重

    NSArray*arr=@[@"first",@"second",@"first"];

    arr=[arrvalueForKeyPath:@"@distinctUnionOfObjects.self"];

    NSLog(@"%@",arr);