How to remove an element from a split String?

Question

I'm trying to remove an element/item/entry from a split string.

Let's say I got the string [string_] as follows:

string string_ = "one;two;three;four;five;six";

Then I split this string to get each, let's say, item:

string[] item = (string_.Split(";"));

I have no informations other than from variables. Depending on the user choice, I can get an item value and index.

Let's say that for this example, the user chose "four" which is the index "3".

How can I make my string look like the index 3 have been deleted, as string_ would be equal to the following:

"one;two;three;five;six"

I've tried multiple things and it seems like the only solution is to go through a char method.

Is that true or did I miss something?

---

EDIT to suggested already_posted_answer : Not quite the same question as my ITEM could be placed anywhere in my splitted string depending on the user selection.

Answer 1

First of all you need to write better variable names, string_ is a horrible name. Even something like "input" is way better.

string input = "one;two;three;four;five;six";

Next, you are on the right track by using Split(). This will return an array of string:

string[] splitInput = input.Split(";");

The resulting string array will look like this:

//string[0] = one
//string[1] = two
//string[2] = three
//string[3] = four
//string[4] = five
//string[5] = six

Removing with known index

If you want to remove a specific element from the array, you could make the result of Split() a List<T> by using ToList() instead and utilize the RemoveAt() method of the resulting List<T>:

List<string> splitList = input.Split(';').ToList();
splitList.RemoveAt(3);

//Re-create the string
string outputString = string.Join(";", splitList);
//output is: "one;two;three;five;six"

Remove all strings that match an input

If you need to remove items from the list without knowing their index but knowing the actual string, you can use LINQ's Where() to filter out the matching items:

//Get the input from the user somehow
string userInput = Console.ReadLine();
IEnumerable<string> filteredList = input.Split(';')
                                      .Where(x => string.Compare(x, userInput, true) != 0);

//Re-create the string
string outputString = string.Join(";", filteredList);

I made a fiddle to demonstrate both methods here

Answer 2

You can convert an array of string to list by following:

var list = new List<string>(item);

Once the list is created, you can easily remove an element:

var index = list.IndexOf("four");
list.RemoveAt(index);

Join the string back:

var result = String.Join(";", list.ToArray());

Result:

Answer 3

You can convert your string array into a List<string>, and since you have the index of the item to be removed, you can remove the item using RemoveAt, then join the items back into one string.

Here's a complete console application example:

static void Main(string[] args)
{
    string string_ = "one;two;three;four;five;six";
    string[] items = (string_.Split(';'));

    Console.WriteLine("Please select an item to remove:");
    for (int i = 0;i<items.Length;i++)
    {
        Console.WriteLine(string.Format("{0}- {1}", (i + 1).ToString(), items[i]));
    }
    int num = 0;
    int.TryParse(Console.ReadLine(), out num);
    if (num > 0 && num <= items.Length)
    {
        List<string> itemsList = items.ToList();
        itemsList.RemoveAt(num - 1);
        string newString = string.Join(";", itemsList);
        Console.WriteLine(string.Format("The new string is: {0}", newString));
    }
    else
    {
        Console.WriteLine("Invalid number!");
    }
    Console.ReadLine();
}

Hope that helps.

Answer 4

We can employ LINQ. Initial plan is to split the string, then create a union of two enumerables: before and after the item. Something like this:

    // preconditions
    const int idx = 3;
    string string_ = "one;two;three;four;five;six";

    // actual transformation
    string[] item = (string_.Split(';'));
    var iterator = item.Take(idx).Concat(item.Skip(idx + 1));

    // output the results
    var result = string.Join(";", iterator);
    Console.Write(result);

Answer 5

Would this work for you?

If you create a new string like this, then replace the value of string_ with the value of the new string.

string string_ = "one;two;three;four;five;six";
string newstring = string_.Replace("four", "");
string_ = newstring.Replace(";;", ";");