比如有一个数组：

NSArray *arr = @[@"1", @"2", @"3"];

倒过来排序：
arr = [[arr reverseObjectEnumerator] allObjects];


NSMutableArray *accountArr = [NSMutableArray arrayWithContentsOfFile:filePath];

    self.accountArr = (NSMutableArray *)[[accountArr reverseObjectEnumerator] allObjects];