How to compare two lists of integers in c#

here

		List<int> iList = new List<int>()
		{1, 2, 3, 4};

/*
What I need are actions such as:
1) Remove item "1" from index 0
2) Add item "5" to index 0
3) Add item "7" to index 1
*/
		iList.Remove(1);
		iList.Insert(0, 5);
		iList.Insert(1, 7);

		foreach (int i in iList)
		{
			Console.WriteLine(i);
		}

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result

5
7
2
3
4

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https://dotnetfiddle.net/Bg0WmA

Thanks HainKurt.
I am afraid that wasn't my question.

>> I would like to determine a course of actions that instructs a user how to produce the new list from the old list.
What I need is how to analyze the two lists and produce the course of actions.
With the course of actions, a user can take the original list and come up with a new list.

I dont get what you need...

can you give any example?

An example is, I have two lists:
list A:  1, 2, 3, 4
list B:  5, 7, 2, 3, 4

Presumably, a user has knowledge of list A, i.e. 1, 2, 3, 4
If I want to inform the user about the content of list B, I could either give him the entire new list B.
Or, I could simply tell him to replace the first number "1" in his list by "5" and "7".

My question is how my C# program be able to analyze and compare the two lists A and B, and come up with the instruction: replace the first number "1" by "5" and "7".

Normal LINQ 'Except' or 'Intercept' probably wont' work in this case.

Thanks.

I think I got that figured out.

var intersected = old_list.Intersect(new_list);

var resultsA = intersected.ToDictionary(x => x, x => old_list.IndexOf(x));
var resultsB = intersected.ToDictionary(x => x, x => new_list.IndexOf(x));

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My code allows me to construct a new list based upon the common numbers. The following were output from my code.

Numbers: 2, 3, 4
Indices in old list: 1, 2, 3

Numbers: 2, 3, 4
Indices in new list: 2, 3, 4

Move value at old list[1] to new list[2]
Move value at old list[2] to new list[3]
Move value at old list[3] to new list[4]

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What I didn't put down was to construct the new numbers "5" and "7" which can be obtained by comparing the "new_list" and the list in "resultsB". This gave me:

Add '5' to new list[0]
Add '7' to new list[1]

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Thanks for your help.

Thanks Chris.