iOS 开发后台返回数据分类

前情提要：
后台返回了一堆数据，格式如下

后台返回的数据

要求：根据area_id进行分类，1-6分别代表不同洲，每个洲最多只取前三个国家，如果超出则用...代替。
效果图

完成后效果图
思路，得到返回数据后，通过area_id遍历数组，得到每个洲，然后在每一中洲里面进行判断字符串拼接。
上代码
1.懒加载模拟数据

-(NSArray *)datasArray
{
    if (!_datasArray) {
        _datasArray = @[@{@"apn":@"uinternet",@"area_id":@"1",@"country_name":@"亚美尼亚",@"network_type":@"4G"},
            @{@"apn":@"3gnet",@"area_id":@"2",@"country_name":@"奥地利",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"1",@"country_name":@"中国",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"4",@"country_name":@"澳大利亚",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"5",@"country_name":@"非洲7",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"6",@"country_name":@"美国",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"5",@"country_name":@"非洲6",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"3",@"country_name":@"乌拉圭",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"4",@"country_name":@"纽西兰",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"5",@"country_name":@"非洲5",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"1",@"country_name":@"日本",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"2",@"country_name":@"奥地利",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"5",@"country_name":@"非洲4",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"6",@"country_name":@"加拿大",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"3",@"country_name":@"巴拉圭",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"2",@"country_name":@"奥地利",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"1",@"country_name":@"韩国",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"4",@"country_name":@"海盗",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"5",@"country_name":@"非洲3",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"6",@"country_name":@"北美1",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"3",@"country_name":@"阿根廷",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"2",@"country_name":@"奥地利",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"1",@"country_name":@"朝鲜",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"4",@"country_name":@"不知名笑道",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"5",@"country_name":@"非洲2",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"6",@"country_name":@"北美2",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"5",@"country_name":@"非洲1",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"2",@"country_name":@"奥地利",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"4",@"country_name":@"大洋洲1",@"network_type":@"Optus"},
            @{@"apn":@"3gnet",@"area_id":@"3",@"country_name":@"巴西",@"network_type":@"Optus"}
            ];
    }
    return _datasArray;
}

2.处理数据

//定义好每个洲字符串
 NSString *countryName= @"";
 NSString *asiaStr = @"";
 NSString *europStr = @"";
 NSString *africaStr = @"";
 NSString *oceanStr = @"";
 NSString *northAmericaStr = @"";
 NSString *southAmericaStr = @"";
 //定义好每个洲所拥有的的国家的个数
 NSInteger asiaCount = 0;
 NSInteger europCount = 0;
 NSInteger africaCount = 0;
 NSInteger oceanCount = 0;
 NSInteger northAmericaCount = 0;
 NSInteger southAmericaCount = 0;
3.遍历数组
for (NSDictionary * dic in self.datasArray) {
        NSString * names = dic[@"country_name"];
        switch ([dic[@"area_id"] integerValue]) {
            case 1:
            {
                asiaCount+=1;
                if (asiaCount ==4) {
                    asiaStr = [asiaStr stringByAppendingString:@"..."];
                }else if (asiaCount <= 3){
                    if (asiaCount == 1) {
                        asiaStr = [NSString stringWithFormat:@"Aisa:%@",names];
                    }else{
                        asiaStr = [asiaStr stringByAppendingFormat:@"、%@",names];
                    }
                }
                
            }
                break;
            case 2:
                {
                    europCount+=1;
                    if (europCount ==4) {
                        europStr = [europStr stringByAppendingString:@"..."];
                    }else if (europCount <= 3){
                        if (europCount == 1) {
                            europStr = [NSString stringWithFormat:@"Europe:%@",names];
                        }else{
                            europStr = [europStr stringByAppendingFormat:@"、%@",names];
                        }
                    }
                }
        
                break;
            case 3:
                {
                    southAmericaCount+=1;
                    if (southAmericaCount ==4) {
                        southAmericaStr = [southAmericaStr stringByAppendingString:@"..."];
                    }else if (southAmericaCount <= 3){
                        if (southAmericaCount == 1) {
                            southAmericaStr = [NSString stringWithFormat:@"Sourth America:%@",names];
                        }else{
                            southAmericaStr = [southAmericaStr stringByAppendingFormat:@"、%@",names];
                        }
                    }
                }
                break;
            case 4:
                {
                    oceanCount+=1;
                    if (oceanCount ==4) {
                        oceanStr = [oceanStr stringByAppendingString:@"..."];
                    }else if (oceanCount <= 3){
                        if (oceanCount == 1) {
                            oceanStr = [NSString stringWithFormat:@"Oceania:%@",names];
                        }else{
                            oceanStr = [oceanStr stringByAppendingFormat:@"、%@",names];
                        }
                    }
                }
                break;
            case 5:
                {
                    africaCount+=1;
                    if (africaCount ==4) {
                        africaStr = [africaStr stringByAppendingString:@"..."];
                    }else if (africaCount <= 3){
                        if (africaCount == 1) {
                            africaStr = [NSString stringWithFormat:@"Africa:%@",names];
                        }else{
                            africaStr = [africaStr stringByAppendingFormat:@"、%@",names];
                        }
                    }
                }
                break;
            case 6:
                {
                    northAmericaCount+=1;
                    if (northAmericaCount ==4) {
                        northAmericaStr = [northAmericaStr stringByAppendingString:@"..."];
                    }else if (northAmericaCount <= 3){
                        if (northAmericaCount == 1) {
                            northAmericaStr = [NSString stringWithFormat:@"North America:%@",names];
                        }else{
                            northAmericaStr = [northAmericaStr stringByAppendingFormat:@"、%@",names];
                        }
                    }
                }
                break;
        }
    }
4.条件判断，拼接字符串
if (asiaCount>0) {
        countryName = asiaStr;
    }
    
    if (europCount>0) {
        if (countryName.length>0) {
            countryName = [countryName stringByAppendingFormat:@"\n%@",europStr];
        }else{
            countryName = europStr;
        }
    }
    
    if (southAmericaCount>0) {
        if (countryName.length>0) {
            countryName = [countryName stringByAppendingFormat:@"\n%@",southAmericaStr];
        }else{
            countryName = southAmericaStr;
        }
    }
    
    if (oceanCount>0) {
           if (countryName.length>0) {
               countryName = [countryName stringByAppendingFormat:@"\n%@",oceanStr];
           }else{
               countryName = oceanStr;
           }
       }
    
    if (africaCount>0) {
        if (countryName.length>0) {
            countryName = [countryName stringByAppendingFormat:@"\n%@",africaStr];
        }else{
            countryName = africaStr;
        }
    }
    
    if (northAmericaCount>0) {
        if (countryName.length>0) {
            countryName = [countryName stringByAppendingFormat:@"\n%@",northAmericaStr];
        }else{
            countryName = northAmericaStr;
        }
    }

最后打印countryName

Aisa:亚美尼亚、中国、日本...
Europe:奥地利、奥地利、奥地利...
Sourth America:乌拉圭、巴拉圭、阿根廷...
Oceania:澳大利亚、纽西兰、海盗...
Africa:非洲7、非洲6、非洲5...
North America:美国、加拿大、北美1...