如何检查列表中是否包含C＃中的另一个列表项 [英] how to check that a list contains another list item in C#

问题描述

您好，



如何查找字符串已经存在于列表中。例如，如果我想写数据，我现在有一个包含数据的列表在这期间，我希望保持一个条件是否该字符串已经存在于列表中。我使用下面的代码，但它不工作，你可以帮助我

Hello,

How to find a string is already present in a list.For example i have a list that contains data now if i want to write the data in to another list during this i want to keep a condition whether the string is already present in the list.I am using the below code but its not working can you kindly help me

List<list><string>> Messlist
List<string> val= new List<string>();

if (!(Messlist.Contains(val)))
{
---
}

推荐答案

尝试LINQ -

Try LINQ -

var result = Messlist
    .Where(x=> x.Contains(searchString));

你的问题是 val 是另一个List但是包含期望a 字符串



要查看一个列表是否包含另一个列表中的值，请使用List<t>.Intersect [ ^ ]方法并检查计数 任何属性



Eg

Your problem is that val is another List but Contains expects a string

To see if one list contains the values in another use the List<t>.Intersect[^] method and check against the Count Any property

E.g.

private void button1_Click(object sender, EventArgs e)
{
    var l1 = new List<string> {"1", "2", "3", "4", "5", "6"};
    var l2 = new List<string> { "4", "5"};
    var l3 = new List<string> {"7", "8"};

    ListCheck(l1, l2);
    ListCheck(l1, l3);
}

private static bool ListCheck<T>(IEnumerable<T> l1, IEnumerable<T> l2)
{
    // TODO: Null parm checks
    if (l1.Intersect(l2).Any())
    {
        Console.WriteLine("matched");
        return true;
    }
    else
    {
        Console.WriteLine("not matched");
        return false;
    }
}

或更改 val 是一个字符串

这是一个很好的例子。

试试这个





http：// www.dotnetperls.com/intersect [ ^ ]



http://stackoverflow.com / questions / 7187996 / intersect-two-list-in-c-sharp [ ^ ]

Here is some good example for you.
Try this


http://www.dotnetperls.com/intersect[^]

http://stackoverflow.com/questions/7187996/intersect-two-list-in-c-sharp[^]

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