如何在集合中找到一个对象,其中集合具有相同类型的子集合?
问题描述:
如果我有一个Collection<T>
,每个T
对象可以有一个孩子Collection<T>
以及一个Collection<T2>
,是如何找到的T2
目标的最佳途径,在那里我知道T2
对象的string name
,我有一个Collection<T>
?如何在集合中找到一个对象,其中集合具有相同类型的子集合?
答
递归搜索实例级别T2集合和子T集合,直到找到匹配项。
public T2 Find(T primaryObject, string searchValue)
{
var secondaryObject = primaryObject.T2Collection.SingleOrDefault(x => x.Name == searchValue)
if (secondaryObject != null)
return secondaryObject;
foreach (var childObject in primaryObject.T1Collection)
{
secondaryObject = Find(childObject, searchValue);
if (secondaryObject != null)
return secondaryObject;
}
return null;
}
答
你需要一个递归的方法来搜索所有T2匹配搜索值:
public class Program
{
private static IEnumerable<Bar> Find(Foo foo, String name)
{
foreach (var x in foo.Bars.Where(x => x.Name == name))
yield return x;
var bars = foo.Foos?.SelectMany(x => Find(x, name)) ?? new Bar[0];
foreach (var y in bars)
yield return y;
}
public static void Main(String[] args)
{
var foo = new Foo
{
Bars = new List<Bar>
{
new Bar { Name = "n1" },
new Bar { Name = "n2" },
new Bar { Name = "n3" },
new Bar { Name = "n4" }
},
Foos = new List<Foo>
{
new Foo
{
Bars = new List<Bar>
{
new Bar { Name = "n1" },
new Bar { Name = "n2" },
new Bar { Name = "n3" },
new Bar { Name = "n4" }
},
Foos = new List<Foo>
{
new Foo
{
Bars = new List<Bar>
{
new Bar { Name = "n1" },
new Bar { Name = "n2" },
new Bar { Name = "n3" },
new Bar { Name = "n4" }
}
}
}
},
new Foo
{
Bars = new List<Bar>
{
new Bar { Name = "n1" },
new Bar { Name = "n2" },
new Bar { Name = "n3" },
new Bar { Name = "n4" }
}
}
}
};
foreach (var x in Find(foo, "n1"))
Console.WriteLine(x.Name);
Console.ReadLine();
}
}
public class Foo
{
#region Properties
public IEnumerable<Foo> Foos { get; set; }
public IEnumerable<Bar> Bars { get; set; }
#endregion
}
public class Bar
{
#region Properties
public String Name { get; set; }
#endregion
}
答
无扩展名通常可以用来代替递归函数:
using System.Reactive.Linq;
public class T2
{
public string Name;
}
public class T
{
public IEnumerable<T2> t2Collection;
public IEnumerable<T> tCollection;
}
public T2 Find(IEnumerable<T> primaryCollection, string searchValue)
{
T2 result = null;
Observable.Generate(
new
{
currentCollection = primaryCollection,
searchedT2 = default(T2)
},
state => state.searchedT2 == default(T2),
state => new
{
currentCollection = state.currentCollection.SelectMany(t => t.tCollection),
searchedT2 = state.currentCollection.SelectMany(t => t.t2Collection).FirstOrDefault(t2 => t2.Name == searchValue)
},
state => state.searchedT2
).Subscribe(t2=>result=t2);
return result;
}
我认为这是一个最好的方法是提取一些接口并在T和T2类型中实现它。你能展示T或T2类的例子吗? –