Question

I have a List<string[]> called lst:

[0] "ABC" "DEF" "GHI"
[1] "JKL" "MNO" "PQR"
[2] etc, etc...

How do I add another string to the end of each lst member?

string s = “EndOfBlock”;

[0] "ABC" "DEF" "GHI" "EndOfBlock"
[1] "JKL" "MNO" "PQR" "EndOfBlock"
[2] etc, etc...

Thank you.

Answer 1

As the commenters have noted, it sounds like you really want a List<List<string>>. But if you want to stick with a List<string[]>, here’s how I’d expand each array.

List<string[]> list = ...
for(int i = 0; i < list.Count; i++)
{
    // copy to a local variable (list[i] is a property, which can't be passed 'ref')
    string[] array = list[i];

    // resize the local variable. (this creates a new string[] object)
    Array.Resize(ref array, array.Length + 1);
    array[array.Length - 1] = "EndOfBlock";

    // put the new object back in the list, replacing the old smaller one.
    list[i] = array;
}