数组排序［Block，NSComparator］

NSArray *stringArray = [NSArray arrayWithObjects:@"abc 1", @"abc 21", @"abc 12",@"abc 13",@"abc 05",nil];
        NSComparator sortBlock = ^(id string1, id string2)
       {
            return [string1 compare:string2];
       };
       NSArray *sortArray = [stringArray sortedArrayUsingComparator:sortBlock];
       NSLog(@"sortArray:%@", sortArray);