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c#linqlambda
Ale Garcia
Ale Garcia

Reputation: 190

List Categories and it's count of products with LinQ using Lambda or classic expressions

I need to list the categories and the count of the products that belong to each category using LinQ lambda or classic expressions.

This is the Class:

  class Product
    {
        public int ProductID { get; set; }
        public string ProductName { get; set; }
        public string Category { get; set; }
        public decimal UnitPrice { get; set; }
        public int UnitsInStock { get; set; }
    }

This is the list I am using just to figure out how the list looks like.

  IEnumerable<Product> productList = new List<Product>  {
          new Product  { ProductID = 1, ProductName = "Chai", Category = "Beverages",
            UnitPrice = 18.0000M, UnitsInStock = 39 },
          new Product{ ProductID = 2, ProductName = "Chang", Category = "Beverages",
            UnitPrice = 19.0000M, UnitsInStock = 17 },
          new Product{ ProductID = 3, ProductName = "Aniseed Syrup", Category = "Condiments",
            UnitPrice = 10.0000M, UnitsInStock = 13 },
          new Product{ ProductID = 4, ProductName = "Chef Anton's Cajun Seasoning", Category = "Condiments",......and so on..

I have a method that returns a list called listProd. For instance, I am able to get the count of products in "Beverages" category individually, but this way I have to create as many queries as Categories are...(not good)..

int query = listProd.Where(p => p.Category == "Beverages").Count();

So what I want is to create query something like this:

Category, count(products that belongs to the Category)

Beverages, 5

Condiments, 7

Upvotes: 1

Views: 2270

Answers (2)

Mighty Badaboom
Mighty Badaboom

Reputation: 6155

You could use this LINQ query

 var result = productList.GroupBy(x => x.Category)
                         .Select(y => new { Category = y.Key, Count = y.Count() });

First group by the category and then use Key and Count() to get the result objects.

With the sample data you've provided the result will look like

enter image description here

If you want to get more information and samples about LINQ I recommend 101 LINQ Samples.

edit

Accoring to your comment:

You could use the Where statement to get only categorie which have more than 4 products.

var result = productList.GroupBy(x => x.Category)
                        .Where(x => x.Count() > 4)
                        .Select(y => new { Category = y.Key, Count = y.Count() });= y.Count() });

Upvotes: 4

Koderzzzz
Koderzzzz

Reputation: 869

Use the following peace code

  IEnumerable<Product> productList = new List<Product>  {
      new Product  { ProductID = 1, ProductName = "Chai", Category = "Beverages",
        UnitPrice = 18.0000M, UnitsInStock = 39 },
      new Product{ ProductID = 2, ProductName = "Chang", Category = "Beverages",
        UnitPrice = 19.0000M, UnitsInStock = 17 },
      new Product{ ProductID = 3, ProductName = "Aniseed Syrup", Category = "Condiments",
        UnitPrice = 10.0000M, UnitsInStock = 13 },
      new Product{ ProductID = 4, ProductName = "Chef Anton's Cajun Seasoning", Category = "Condiments"}


    };
        var list = (from x in productList
                    group x.Category by x.Category into g
                    select new { Category = g.Key, Count = g.Count() });

Upvotes: 3

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