Check individual items from a list of Valuetuple in c# 7

Question

Please consider the following list of ValueTuple C#7

List<(double prices, int matches)> myList = new List<(double, int)>();

                    myList.Add((100, 9));  

                    myList.Add((100.50 , 12));

I can do Foreach var i in myList, myList.Max, myList.Average etc and it will return both types of the ValueTuple.

But, how can I check and return only the values for prices and/or matches? Can you post examples please?

score 3 · Accepted Answer · answered Jul 20 '18 at 11:06

Pattern-matching can be used to deconstruct the tuple in a for-each statement

List<(double prices, int matches)> myList = new List<(double, int)>();
myList.Add((100, 9));
myList.Add((100.50, 12));

foreach (var (price, match) in myList)
{
    Console.WriteLine($"Price: {price}");
    Console.WriteLine($"Match: {match}");
}

score 1 · Answer 2 · answered Jul 14 '18 at 11:53

1

You can just use the Select(x => x.prices)

static void Main(string[] args)
{
    List<(double prices, int matches)> myList = new List<(double, int)>();
    myList.Add((100, 9));
    myList.Add((100.50, 12));

    var prices = myList.Select(x => x.prices);
    var matches = myList.Select(x => x.matches);

    Console.WriteLine("prices:");
    foreach (var item in prices)
        Console.WriteLine(item);

    Console.WriteLine("\nmatches:");
    foreach (var item in matches)
        Console.WriteLine(item);

    Console.Read();
}

Output:

prices:
100
100.5

matches:
9
12

answered Jul 14 '18 at 11:53

L_J

2,351
10
23
28

1

Thanks very much!! Simple and powerful!! – Roblogic Jul 14 '18 at 12:43
And how can this be done if instead of returning "prices" and "matches" in a IEnumerable, these are returned inside a new List? Is that possible to do it direct or it needs the Select to return the values as IEnumerable and then add them to a List ? – Roblogic Jul 15 '18 at 00:30

donatasj87 · Answer 3 · 2021-04-23T10:16:11.623

0

I prefer this approach:

var _someCollection = new List<(int Id, string Name)> { (123, "abc") };
...
_someCollection.ForEach(_ => {
   _.Id = 1;
   _.Name = "a";
});

In this case you do not need to redefine names as needed in simple foreach statement, which can lead to bugs and harder to debug code if renamed differently.

edited Apr 23 '21 at 10:16

answered Nov 04 '19 at 11:25

donatasj87

760
9
23

Check individual items from a list of Valuetuple in c# 7

3 Answers3