代码之家 › 专栏 › 技术社区 › Thorin Oakenshield

在C语言中使用LINQ比较字典#

linq c#

Thorin Oakenshield · 技术社区 · 14 年前

这两本字典像

Dictionary<String, List<String>> DICTONE = new Dictionary<string, List<String>>();
Dictionary<string, List<String>> DICTTWO = new Dictionary<string, List<String>>();

内容呢

DICTONE["KEY1"]="A"
                "B"
                "C"

DICTONE["KEY2"]="D"
                "E"
                "F"

DICTTWO["KEY1"]="A"
                "B"
                "Z"

DICTTWO["KEY3"]="W"
                "X"
                "Y"

第三个字典有一个类实例作为值

Dictionary<String, MyClass> DICTRESULT = new Dictionary<string, MyClass>();

这个班就像

class MyClass
{
    public List<string> Additional = null;
        public List<string> Missing = null; 

    public MyClass()
        {
            Additional = new List<string>();
            Missing = new List<string>();
        }
        public MyClass(List<string> p_Additional, List<string> p_Missing)
        {
            Additional = p_Additional;
            Missing = p_Missing;
        }
}

如果一个项目在DICTTWO中而不是在DICTTONE中,则将该项目添加到RESULTDICT的附加列表中

预期的答案是

DICTRESULT["KEY1"]=ADDITIONAL LIST ---> "Z"
                   MISSING LIST    ---> "C"

DICTRESULT["KEY2"]=ADDITIONAL LIST ---> ""
                   MISSING LIST    ---> "D"
                                        "E"
                                        "F"
DICTRESULT["KEY3"]=ADDITIONAL LIST ---> ""
                   MISSING LIST    ---> "W"
                                        "X"
                                        "Y"

使用LINQ有什么方法可以做到这一点吗

1 回复 | 直到 14 年前

Jon Skeet 14 年前

好吧,这是一个尝试,假设 first 和 second 是有问题的词典。

var items = from key in first.Keys.Concat(second.Keys).Distinct()
            let firstList = first.GetValueOrDefault(key) ?? new List<string>()
            let secondList = second.GetValueOrDefault(key) ?? new List<string>()
            select new { Key = key,
                         Additional = secondList.Except(firstList),
                         Missing = firstList.Except(secondList) };
var result = items.ToDictionary(x => x.Key,
                                x => new MyClass(x.Additional, x.Missing));

public static TValue GetValueOrDefault<TKey, TValue>
    (this IDictionary<TKey, TValue> dictionary,
     TKey key)
{
    TValue value;
    dictionary.TryGetValue(key, out value)
    return value;
}

推荐文章

SpaceCowboy74 Mohammad Aghazadeh · 使用Fluent Validation比较数组中的值

3 月前