LINQ 条件串联查询

Question

我是一个 LINQ 新手，正在从事涉及国际邮政地址的 GIS 项目。我的设计问题之一涉及将键/值对格式的分解地址数据动态转换为按国家/地区划分的多行邮政地址格式。每条记录都需要根据国家/地区字段值、根据国家/地区和地址行定义的一组规则自行编写：

Dictionary<string, string> addressOne = new Dictionary<string,string>() {
    { "StreetName", "Stradă Măguricea" },
    { "HouseNumber", "1" },
    { "ApartmentLabel", "Ap" },
    { "ApartmentNumber", "17" },
    { "PostalCode", "014231" },
    { "City", "BUCUREŞTI" },
    { "Country", "Romania" }
};

Dictionary<string, string> addressTwo = new Dictionary<string,string>() {
    { "StreetName", "PORTAGE" },
    { "StreetSuffix", "AVE" },
    { "HouseNumber", "811" },
    { "City", "WINNIPEG" },
    { "StateProvince", "MB" },
    { "PostalCode", "R3B 2A8" },
    { "Country", "CANADA" }
};

//Example Concatenation Rules (these are approximations)...

//Romania:  AddressLine1 = "{StreetName}[ {StreetSuffix}] {HouseNumber}[, {ApartmentLabel} {ApartmentNumber}"
//          AddressLine2 = "{PostalCode} {City}"
//          AddressLine3 = "{Country}"

//Canada:   AddressLine1 = "{HouseNumber} {StreetName}[ {StreetSuffix}]"
//          AddressLine2 = "[{ApartmentLabel} {ApartmentNumber}]"
//          AddressLine3 = "{City} {StateProvince} {PostalCode}"
//          AddressLine4 = "{Country}"

我目前正在计划一个由 国家/地区< 调用的函数表/code> 和 AddressLine，每个 Func 返回一个由适当的串联规则格式化的复合字段。我始终可以使用传统的 StringBuildler 逻辑来实现这些规则函数，但这对于 LINQ 查询来说似乎已经成熟。

我的大部分搜索都会出现常见的逗号聚合场景；这更多的是一个选择性的、条件模式匹配问题（我已经闻到了正则表达式的味道）。这是 LINQ 的一个很好的用例，还是我应该坚持老式的分支字符串操作？

感谢您的阅读！

Answer 1

我喜欢 Linq 和字典：

public static IEnumerable<string> InjectFields(IDictionary<string, string> address)
{
    string country = address["Country"];
    return formatStrings[country]
            .Select(s => address.Aggregate(s, (acc, pair) => acc.Replace("{"+pair.Key+"}", pair.Value)))
            .ToArray();
}

private static Dictionary<string, IEnumerable<string>> formatStrings = 
             new Dictionary<string, IEnumerable<string>>(StringComparer.InvariantCultureIgnoreCase)
                    {
                        { "Romania", new[] {
                            "{StreetName}[ {StreetSuffix}] {HouseNumber}[, {ApartmentLabel} {ApartmentNumber}",
                            "{PostalCode} {City}",
                            "{Country}",
                        } },
                        { "Canada", new[] {
                            "{HouseNumber} {StreetName}[ {StreetSuffix}]",
                            "[{ApartmentLabel} {ApartmentNumber}]",
                            "{City} {StateProvince} {PostalCode}",
                            "{Country}"
                        } },
                    };