c# 字典Dictionary相关操作（遍历、求交、差、并集）

遍历字典

            foreach (KeyValuePair<string, string> kvp in dic)
            {
                if (kvp.Value.Equals("2"))
                { 
                    //...... kvp.Key;
                }
            }
 
            //foreach dic.Keys
            foreach (string key in dic.Keys)
            {
                if (dic[key].Equals("2"))
                { 
                    //...... key
                }
            }

对两个字典（键相同就认为相同）求交集、并集和差集（List和数组同理）

Dictionary<string, int> dt1 = new Dictionary<string, int>();
for (int i = 0; i < 10000; i++)
{
　　dt1.Add(i.ToString(), i);
}

Dictionary<string, int> dt2 = new Dictionary<string, int>();
for (int i = 1000; i < 11000; i++)
{
　　dt2.Add(i.ToString(), i);
}

//求交集

var dz = dt1.Keys.Intersect(dt2.Keys);
foreach (var i in dz)
{
 　　Console.Write(i + " ");
}
Console.WriteLine("====");
//求差集
var dz2 = dt1.Keys.Except(dt2.Keys);

foreach (var i in dz2)
{
 　　Console.Write(i + " ");
}
Console.WriteLine("====");
//求并集
var dz3 = dt1.Keys.Union(dt2.Keys);

foreach (var i in dz3)
{
 　　Console.Write(i + " ");
}

c# Dictionary求交集、差集、并集