排序

NSArray * array = @[@"aZ",@"ZbcAc",@"ZbcAb",@"Zd",@"Zw",@"Zz"];

    NSArray * array2 = [array sortedArrayUsingComparator:^NSComparisonResult(NSString * obj1, NSString * obj2) {

        return [obj1 compare:obj2 options:NSCaseInsensitiveSearch];

    }];

    NSLog(@"%@",array2);

输出结果
   aZ,

    ZbcAc,

    ZbcAb,

    Zd,

    Zw,

    Zz