c# split list of tuple into multiple lists

Question

Assuming I have the following list of tuples:

List<Tuple<string, string>>

{"Name", "xx"},{"Age", "25"},{"PostalCode", "12345"},{"Name", "yy"},{"Age", "30"},{"PostalCode", "67890"}

I want to split this list into multiple lists. Splitting criteria is Item1 == "Name"

Result should be following:

List 1:

{"Name", "xx"},{"Age", "25"},{"PostalCode", "12345"}

List 2:

{"Name", "yy"},{"Age", "30"},{"PostalCode", "67890"}

I have a solution where I note down the indexes of "Name" in the original list and create new lists by using the function GetRange. But there must be a better and faster way of doing this?

Why wouldn't you create a simple class that holds your data? — jAC
– jAC, Commented Feb 28, 2018 at 12:26
These tuples are of different types, <string, string> or <string, int> how you keep them originally? — Johnny
– Johnny, Commented Feb 28, 2018 at 12:33
I have edited my question. List contains a tuple of <string, string>. Am getting data like this from an external interface. — stackoverflow_user_
– stackoverflow_user_, Commented Feb 28, 2018 at 12:43

Rotem · Accepted Answer · 2018-02-28 13:07:28Z

4

You can use LINQ to find all the indices of Name and select it and the following 3 entries into a new list.

This assumes that the original list is well-formed such that for every Name there is guaranteed to be two valid fields following it.

var data = new List<Tuple<string, string>>
{
    new Tuple<string, string>("Name", "xx"),
    new Tuple<string, string>("Age", "25"),
    new Tuple<string, string>("PostalCode", "12345"),
    new Tuple<string, string>("ignoreMe", "345"),
    new Tuple<string, string>("Name", "yy"),
    new Tuple<string, string>("Age", "30"),
    new Tuple<string, string>("PostalCode", "67890")
};

var lists = data
    .Select((x, i) => new { Index = i, Value = x })
    .Where(x => x.Value.Item1 == "Name")
    .Select(x => data.Skip(x.Index).Take(3))
    .ToList();

And also, there are probably more performant solutions than this.

edited Feb 28, 2018 at 13:07

answered Feb 28, 2018 at 13:02

Rotem

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Comments

Slaven Tojić · Accepted Answer · 2018-02-28 13:40:19Z

1

You can use Enumrable.Range to loop trough your list and select your desired tuples:

List<Tuple<string, string>> data = new List<Tuple<string, string>>
{
    new Tuple<string, string>("Name", "xx"),
    new Tuple<string, string>("Age", "25"),
    new Tuple<string, string>("PostalCode", "12345"),
    new Tuple<string, string>("Name", "yy"),
    new Tuple<string, string>("Age", "30"),
    new Tuple<string, string>("PostalCode", "67890")
};

var result = Enumerable.Range(0, data.Count).Where(i => data[i].Item1 == "Name")
            .Select(i => data.Skip(i).Take(3).ToList())
            .ToList();

You can test my code here : https://dotnetfiddle.net/6fJumx

edited Feb 28, 2018 at 13:40

answered Feb 28, 2018 at 13:20

Slaven Tojić

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