如何删除添加到列表中的最后一个元素？

Question

I have a List in c# in which i am adding list fields.Now while adding i have to check condition,if the condition satisfies then i need to remove the last row added from the list. Here is my sample code..

    List<> rows = new List<>();
    foreach (User user in users)
    {
        try
        {
            Row row = new Row();
            row.cell = new string[11];
            row.cell[1] = user."";
            row.cell[0] = user."";
            row.cell[2] = user."";         

            rows.Add(row);

            if (row.cell[0].Equals("Something"))
            {

                //here i have to write code to remove last row from the list
                //row means all the last three fields

            }

        }

So my question is how to remove last row from list in c#. Please help me.

Answer 1

我认为最有效的方法是使用RemoveAt ：

rows.RemoveAt(rows.Count - 1)

Answer 2

The direct answer to this question is:

if(rows.Any()) //prevent IndexOutOfRangeException for empty list
{
    rows.RemoveAt(rows.Count - 1);
}

However... in the specific case of this question, it makes more sense not to add the row in the first place:

Row row = new Row();
//...      

if (!row.cell[0].Equals("Something"))
{
    rows.Add(row);
}

TBH, I'd go a step further by testing "Something" against user."" , and not even instantiating a Row unless the condition is satisfied, but seeing as user."" won't compile, I'll leave that as an exercise for the reader.

Answer 3

rows.RemoveAt(rows.Count - 1);

Answer 4

您可以使用List<T>.RemoveAt方法：

rows.RemoveAt(rows.Count -1);

Answer 5

if you need to do it more often , you can even create your own method for pop the last element; something like this:

public void pop(List<string> myList) {
    myList.RemoveAt(myList.Count - 1);
}

or even instead of void you can return the value like:

public string pop (List<string> myList) {
    // first assign the  last value to a seperate string 
    string extractedString = myList(myList.Count - 1);
    // then remove it from list
    myList.RemoveAt(myList.Count - 1);
    // then return the value 
    return extractedString;
}

just notice that the second method's return type is not void , it is string b/c we want that function to return us a string ...

Answer 6

I would rather use Last() from LINQ to do it.

rows = rows.Remove(rows.Last());

or

rows = rows.Remove(rows.LastOrDefault());