Develop Reference

Split a single list to 'x' numbers of lists during runtime? [duplicate]

I have an object:
public class Customer
{
public int ID { get; set; }
public string Name { get; set; }
public int GroupID { get; set; }
}
I return a list that may look like the following:
List<Customer> CustomerList = new List<Customer>();
CustomerList.Add( new Customer { ID = 1, Name = "One", GroupID = 1 } );
CustomerList.Add( new Customer { ID = 2, Name = "Two", GroupID = 1 } );
CustomerList.Add( new Customer { ID = 3, Name = "Three", GroupID = 2 } );
CustomerList.Add( new Customer { ID = 4, Name = "Four", GroupID = 1 } );
CustomerList.Add( new Customer { ID = 5, Name = "Five", GroupID = 3 } );
CustomerList.Add( new Customer { ID = 6, Name = "Six", GroupID = 3 } );
I want to return a linq query which will look like
CustomerList
GroupID =1
UserID = 1, UserName = "UserOne", GroupID = 1
UserID = 2, UserName = "UserTwo", GroupID = 1
UserID = 4, UserName = "UserFour", GroupID = 1
GroupID =2
UserID = 3, UserName = "UserThree", GroupID = 2
GroupID =3
UserID = 5, UserName = "UserFive", GroupID = 3
UserID = 6, UserName = "UserSix",
I tried from
Using Linq to group a list of objects into a new grouped list of list of objects
code
var groupedCustomerList = CustomerList
.GroupBy(u => u.GroupID)
.Select(grp => grp.ToList())
.ToList();
works but does not give the desired output.

var groupedCustomerList = CustomerList.GroupBy(u => u.GroupID)
.Select(grp =>new { GroupID =grp.Key, CustomerList = grp.ToList()})
.ToList();

var groupedCustomerList = CustomerList
.GroupBy(u => u.GroupID, u=>{
u.Name = "User" + u.Name;
return u;
}, (key,g)=>g.ToList())
.ToList();
If you don't want to change the original data, you should add some method (kind of clone and modify) to your class like this:
public class Customer {
public int ID { get; set; }
public string Name { get; set; }
public int GroupID { get; set; }
public Customer CloneWithNamePrepend(string prepend){
return new Customer(){
ID = this.ID,
Name = prepend + this.Name,
GroupID = this.GroupID
};
}
}
//Then
var groupedCustomerList = CustomerList
.GroupBy(u => u.GroupID, u=>u.CloneWithNamePrepend("User"), (key,g)=>g.ToList())
.ToList();
I think you may want to display the Customer differently without modifying the original data. If so you should design your class Customer differently, like this:
public class Customer {
public int ID { get; set; }
public string Name { get; set; }
public int GroupID { get; set; }
public string Prefix {get;set;}
public string FullName {
get { return Prefix + Name;}
}
}
//then to display the fullname, just get the customer.FullName;
//You can also try adding some override of ToString() to your class
var groupedCustomerList = CustomerList
.GroupBy(u => {u.Prefix="User", return u.GroupID;} , (key,g)=>g.ToList())
.ToList();

is this what you want?
var grouped = CustomerList.GroupBy(m => m.GroupID).Select((n) => new { GroupId = n.Key, Items = n.ToList() });

var result = from cx in CustomerList
group cx by cx.GroupID into cxGroup
orderby cxGroup.Key
select cxGroup;
foreach (var cxGroup in result) {
Console.WriteLine(String.Format("GroupID = {0}", cxGroup.Key));
foreach (var cx in cxGroup) {
Console.WriteLine(String.Format("\tUserID = {0}, UserName = {1}, GroupID = {2}",
new object[] { cx.ID, cx.Name, cx.GroupID }));
}
}

The desired result can be obtained using IGrouping, which represents a collection of objects that have a common key in this case a GroupID
var newCustomerList = CustomerList.GroupBy(u => u.GroupID)
.Select(group => new { GroupID = group.Key, Customers = group.ToList() })
.ToList();

Convert flat db row data to nested typed objects linq

I'm getting the results of a sql outer join as flat results in an IEnumerable, and would like to convert them to nested typed objects in linq. From something like this:
[{id: 1, industryId: 1}, {id:1, industryId: 2}, {id:2, industryId: 1} etc..]
to something like this:
list of Company [{id: 1, list of Industry{industryId: 1, 2}, {id: 2, list of Industry{industryId: 1}}]
I'm currently trying a solution with GroupBy:
Companies = flatDbRows
.GroupBy(
row => row.CompanyId,
(key, value) => new CompanyModel
{
CompanyId = value.First().CompanyId,
CompanyName = value.First().CompanyName,
Industries = value
.GroupBy(
row => new { row.IndustryId, row.Industry },
(k, v) => new IndustryModel() { IndustryId = k.IndustryId, Name = k.Industry }
)
.Where(x => x.IndustryId != 0)
.ToList(),
}).ToList();
}
but it doesn't feel great, especially with all the value.First() I'm using to get the values that only belong to each grouped company. Is there something more appropriate? Group join sounded more like what I wanted, but I'm having trouble understanding how to apply it to a single list. I'm open to using query syntax instead of the lambdas if that's easier.
I'm trying to go from this model (where company-related info will be duplicated for each outer joined industry result):
public class CompanyFlatDbRowsModel
{
public int CompanyId { get; set; }
public string CompanyName { get; set; }
public int IndustryId{ get; set; }
public string Industry { get; set; }
}
to this:
public class CompanyModel
{
public int CompanyId { get; set; }
public string CompanyName { get; set; }
public IEnumerable<IndustryModel> Industries { get; set; }
}

// FULL edit after providing your models
public class TestClass
{
public class CompanyModel
{
public int CompanyId { get; set; }
public string CompanyName { get; set; }
public List<IndustryModel> Industires { get; set; }
}
public class IndustryModel
{
public int IndustryId { get; set; }
public string IndustryName { get; set; }
}
public class CompanyFlatDbRowsModel
{
public CompanyFlatDbRowsModel()
{
}
public int CompanyId { get; set; }
public string CompanyName { get; set; }
public int IndustryId { get; set; }
public string Industry { get; set; }
}
[Fact]
public void Test()
{
var data = new List<CompanyFlatDbRowsModel>
{
new CompanyFlatDbRowsModel
{
CompanyId = 1,
CompanyName = "Company 1",
IndustryId = 1,
Industry = "Industry 1"
},
new CompanyFlatDbRowsModel
{
CompanyId = 1,
CompanyName = "Company 1",
IndustryId = 2,
Industry = "Industry 2"
},
new CompanyFlatDbRowsModel
{
CompanyId = 2,
CompanyName = "Company 2",
IndustryId = 3,
Industry = "Industry 3"
},
new CompanyFlatDbRowsModel
{
CompanyId = 2,
CompanyName = "Company 2",
IndustryId = 4,
Industry = "Industry 4"
},
};
var result = data.GroupBy(x => x.CompanyId)
.Select(x => new CompanyModel()
{
CompanyId = x.Key,
CompanyName = x.First().CompanyName,
Industires = x.Select(y=> new IndustryModel
{
IndustryName = y.Industry,
IndustryId = y.IndustryId
}).ToList()
}).ToList();
foreach (var item in result)
{
var text = $"Company id : {item.CompanyId}, industries : {string.Join(',',item.Industires.Select(x=>$"(name: {x.IndustryName}, id: {x.IndustryId})"))}";
Debug.WriteLine(text);
}
}
}
output:
Company id : 1, industries : (name: Industry 1, id: 1),(name: Industry 2, id: 2)
Company id : 2, industries : (name: Industry 3, id: 3),(name: Industry 4, id: 4)
edit:
alternatively you can do as below, however the "first" thing still occurs somewhere, I have tried also the GroupJoin but it doesn't really help in that case.
var otherResult = data.Select(x =>
new CompanyModel
{
CompanyId = x.CompanyId,
CompanyName = x.CompanyName,
Industires = data
.Where(y => y.CompanyId == x.CompanyId)
.Select(y => new IndustryModel
{
IndustryId = y.IndustryId,
IndustryName = y.Industry
}).ToList()
})
.GroupBy(y => y.CompanyId)
.Select(x => x.First())
.ToList();
edit:
one more approach without using "first"
var anotherResult = data.GroupBy(x => x.CompanyId)
.Select(x =>
{
var companyModel = new CompanyModel()
{
CompanyId = x.Key
};
companyModel.Industires = x.Select(y =>
{
companyModel.CompanyName = y.CompanyName; // assignign here occurs multiple times however with the same value
return new IndustryModel
{
IndustryId = y.IndustryId,
IndustryName = y.Industry
};
}).ToList();
return companyModel;
}).ToList();

how to dynamically create hierarchy of elements in json? c#

i have a method GetChild(id) that return the children with respect to id of parent passed as a parameter
those children can also have their own children to any level
if i want to create a JSON which represent the entire hierarchy of child and parent then how should i proceed?
public ActionResult GetChild(long id)
{
Dal objDal = new Dal();
var res = objDal.db.ChildGet(id).ToList();
return Json(res, JsonRequestBehavior.AllowGet);
}
this is justfor first level
how can i use this GetChild(id) method recursively?
any kind of help will be appreciated

public class Comment
{
public int Id { get; set; }
public int ParentId { get; set; }
public string Text { get; set; }
public List<Comment> Children { get; set; }
}
public JsonResult Test()
{
List<Comment> categories = new List<Comment>()
{
new Comment () { Id = 1, Text = "Yabancı Dil", ParentId = 0},
new Comment() { Id = 2, Text = "İngilizce", ParentId = 1 },
new Comment() { Id = 3, Text = "YDS", ParentId = 2 },
new Comment() { Id = 4, Text = "TOEFL", ParentId = 2 },
new Comment() { Id = 5, Text = "YDS Seviye1", ParentId = 3 },
new Comment() { Id = 6, Text = "TOEFL Seviye1", ParentId = 4 }
};
List<Comment> hierarchy = new List<Comment>();
hierarchy = categories
.Where(c => c.Id == 2)
.Select(c => new Comment()
{
Id = c.Id,
Text = c.Text,
ParentId = c.ParentId,
Children = GetChildren(categories, c.Id)
})
.ToList();
List<Comment> list = new List<Comment>();
List<string> list2 = new List<string>();
if (hierarchy != null)
{
liste.AddRange(hierarchy);
}
return Json(liste, JsonRequestBehavior.AllowGet);
}
public static List<Comment> GetChildren(List<Comment> comments, int parentId)
{
hAbDbContext db = new hAbDbContext();
return comments
.Where(c => c.ParentId == parentId)
.Select(c => new Comment()
{
Id = c.Id,
Text = c.Text,
ParentId = c.ParentId,
Children = GetChildren(comments, c.Id)
})
.ToList();
}

LINQ Group & Sum on a list of Models where a property is another model

I havent been able to find any answers to this specific question on LINQ Group & Aggregation so am hoping someone here can help. I have a list of models of such:
public class BasketProduct
{
public ProductItem Product { get; set; }
public int Quantity { get; set; }
public decimal SubTotal { get; set; }
public DateTime DateAdded { get; set; }
}
where the first property is another model:
public class ProductItem
{
public int ID { get; set; }
public string Description { get; set; }
public char Item { get; set; }
public decimal Price { get; set; }
public string ImagePath { get; set; }
public string Barcode { get; set; }
}
I basically want to be able to Group and Aggregate on this list:
List<BasketProduct> allBasketProducts =
Using the following:
allBasketProducts = allBasketProducts
.GroupBy(x => x.Product.ID)
.Select(y => new BasketProduct
{
Product.ID = y.First().Product.ID,
Product.Item = y.First().Product.Item,
Product.Description = y.First().Product.Description,
Quantity = y.Sum(z => z.Quantity),
Product.ImagePath = y.First().Product.ImagePath,
Product.Price = y.First().Product.Price,
SubTotal = y.Sum(z => z.SubTotal)
}).ToList();
However it seriously doesn't like this (as per red squigly lines and even red'er text):
Can someone help please?

Your issue isn't actually related to LINQ, it's your ProductItem constructor. You need to construct its nested Product object explicitly, like this:
allBasketProducts
.GroupBy(x => x.Product.ID)
.Select(y => new BasketProduct
{
Quantity = y.Sum(z => z.Quantity),
SubTotal = y.Sum(z => z.SubTotal),
Product = new ProductItem
{
ID = y.First().Product.ID,
Item = y.First().Product.Item,
Description = y.First().Product.Description,
ImagePath = y.First().Product.ImagePath,
Price = y.First().Product.Price
}
}).ToList();

var totals =
(from b in allBasketProducts
group new { b.Quantity, b.SubTotal, Product= b.Product } by b.Product.ID into g
select new BasketProduct
{
Product = g.First().Product,
SubTotal = g.Sum(z => z.SubTotal),
Quantity = g.Sum(z => z.Quantity)
}).ToList();

Try following :
allBasketProducts = allBasketProducts
.GroupBy(x => x.Product.ID)
.Select(y => new BasketProduct()
{
Product = new ProductItem() {
ID = y.First().Product.ID,
Item = y.First().Product.Item,
Description = y.First().Product.Description,
ImagePath = y.First().Product.ImagePath,
Price = y.First().Product.Price
},
Quantity = y.Sum(z => z.Quantity),
SubTotal

When you specify the type of your Select, the compiler expects only the properties of that type. So you can only set the properties Product, Subtotal, Quantity and DateAdded in that code of yours.
You can find the Product simply by selecting the first Product that has an ID that matches your grouping Key:
var allBasketProductsGroupedByProductID = allBasketProducts
.GroupBy(x => x.Product.ID)
.Select(y => new BasketProduct
{
Product = y.First(i => i.Product.ID == y.Key).Product,
Quantity = y.Sum(z => z.Quantity),
SubTotal = y.Sum(z => z.SubTotal)
}).ToList();

try this
List allBasketProducts = new List();
allBasketProducts = new List<BasketProduct>()
{
new BasketProduct()
{
Product = new ProductItem()
{
ID = 1,
Price = 5,
},
Quantity = 2,
SubTotal = 2,
},
new BasketProduct()
{
Product = new ProductItem()
{
ID = 1,
Price = 5,
},
Quantity = 4,
SubTotal = 2,
},
new BasketProduct()
{
Product = new ProductItem()
{
ID = 2,
Price = 10,
},
Quantity = 3,
SubTotal = 2,
},
new BasketProduct()
{
Product = new ProductItem()
{
ID = 3,
Price = 20,
},
Quantity = 3,
SubTotal = 2,
},
new BasketProduct()
{
Product = new ProductItem()
{
ID = 2,
Price = 20,
},
Quantity = 3,
SubTotal = 2,
}
};
allBasketProducts = allBasketProducts
.GroupBy(x => x.Product.ID)
.Select(y => new BasketProduct()
{
Product = new ProductItem()
{
ID = y.First().Product.ID,
Item = y.First().Product.Item,
Description = y.First().Product.Description,
ImagePath = y.First().Product.ImagePath,
Price = y.First().Product.Price
},
Quantity = y.Sum(z => z.Quantity),
SubTotal = y.Sum(z => z.SubTotal)
}).ToList();

Query c# List to limit children but return parents

I have a nested list structure with Customers -> Orders -> OrderItems. I am trying to find a LINQ or other query that will return the Customers and their nested items where the OrderItem quantity = 1. However, it should not return any Orders or OrderItems where the quantity != 1.
I have tried this:
var customers2 = customers.Where(c => c.Orders.Any(o => o.OrderItems.Exists(oi => oi.Quantity == 1)));
It correctly returns only Customers with order items quantity = 1, but it also returns all other Orders and Order Items as well.
I can get the desired results with a couple of For-each loops, but I would like to find something more elegant:
foreach (var customer in customers2)
{
customer.Orders = customer.Orders.Where(o => o.OrderItems.Exists(oi => oi.Quantity == 1)).ToList();
foreach (var order in customer.Orders)
{
order.OrderItems = order.OrderItems.Where(oi => oi.Quantity == 1).ToList();
}
}
Here is the object structure and some sample data.
public class Customer
{
public int CustomerId { get; set; }
public string Name { get; set; }
public string Address { get; set; }
public List<Order> Orders { get; set; }
}
public class Order
{
public int OrderId { get; set; }
public int CustomerId { get; set; }
public DateTime OrderDate { get; set; }
public bool Shipped { get; set; }
public List<OrderItem> OrderItems { get; set; }
}
public class OrderItem
{
public int OrderItemId { get; set; }
public int OrderId { get; set; }
public string ItemName { get; set; }
public int Quantity { get; set; }
}
var customers = new List<Customer>
{
new Customer
{
CustomerId = 1,
Name = "Shawn",
Address = "123 Main Street",
Orders = new List<Order>()
{
new Order()
{
OrderId = 100,
CustomerId = 1,
OrderDate = DateTime.Now,
Shipped = true,
OrderItems = new List<OrderItem>()
{
new OrderItem()
{
OrderItemId = 200,
OrderId = 100,
ItemName = "Computer",
Quantity = 1
},
new OrderItem()
{
OrderItemId = 206,
OrderId = 100,
ItemName = "Hard Drive",
Quantity = 2
}
}
},
new Order()
{
OrderId = 106,
CustomerId = 1,
OrderDate = DateTime.Now,
Shipped = true,
OrderItems = new List<OrderItem>()
{
new OrderItem()
{
OrderItemId = 207,
OrderId = 106,
ItemName = "Monitor",
Quantity = 3
},
new OrderItem()
{
OrderItemId = 208,
OrderId = 106,
ItemName = "DVD Burner",
Quantity = 2
}
}
}
}
},
new Customer
{
CustomerId = 2,
Name = "Arianna",
Address = "456 Main Street",
Orders = new List<Order>()
{
new Order()
{
OrderId = 101,
CustomerId = 2,
OrderDate = DateTime.Now.AddDays(-10),
Shipped = true,
OrderItems = new List<OrderItem>()
{
new OrderItem()
{
OrderItemId = 201,
OrderId = 101,
ItemName = "barbie",
Quantity = 2
}
}
}
}
},
new Customer
{
CustomerId = 3,
Name = "Ryan",
Address = "789 Main Street",
Orders = new List<Order>()
{
new Order()
{
OrderId = 102,
CustomerId = 3,
OrderDate = DateTime.Now.AddDays(-5),
Shipped = true,
OrderItems = new List<OrderItem>()
{
new OrderItem()
{
OrderItemId = 203,
OrderId = 103,
ItemName = "Minecraft",
Quantity = 2
}
}
}
}
}
};

You're on the right path with
var customers2 = customers
.Where(c => c.Orders.Any(o => o.OrderItems.Exists(oi => oi.Quantity == 1)));
You just need an additional step as you can't filter the orders and the customers at the same time, you already filtered the customers to get only those you're interested in, now filter the orders themselves
var customers2 = customers
.Where(c => c.Orders.Any(o => o.OrderItems.Exists(oi => oi.Quantity == 1)))
.Select(c => c.Orders.Where(o => o.OrderItems(o => o.OrderItems.Exists(oi => oi.Quantity == 1)));
This however leaves you with an ienumerable of ienumerable of orders, and not the customers, but you can't do exactly what you want (retrieve the customers and have their order property changed) as that would change their original order list, what you can do is create an Anonymous type to store both the orders and Customer in your query in the select as such:
var customers2 = customers
.Where(c => c.Orders.Any(o => o.OrderItems.Exists(oi => oi.Quantity == 1)))
.Select(c => new
{
Customer = c,
FilteredOrders = c.Orders.Where(o => o.OrderItems(o => o.OrderItems.Exists(oi => oi.Quantity == 1))
});
Now you can use this as such
foreach(var cust in customers2)
{
cust.Customer // your original Customer object
cust.Customer.Orders // your original orders collection for this Customer
cust.FilteredOrders // only the orders you're interested in for this customer
}

I imagine there's a shorter solution but this works:
var goodCusts = new List<Customer>();
foreach(var customer in customers)
{
var testCust = customer;
for (int i = testCust.Orders.Count - 1; i >= 0; i--)
{
if (testCust.Orders[i].OrderItems.Count != 1)
testCust.Orders.RemoveAt(i);
}
if (testCust.Orders.Any())
goodCusts.Add(testCust);
}
It does create a new collection, though. It just runs through each customer, removes any Orders with OrderItems.Count != 1, then tests if that customer has any Orders left. If it does, it gets added to the List<Customer> results.

Thanks to #StripplingWarrior I think I have arrived at the answer, though prob still not the most elegant:
var customers2 = customers.Where(x => x.Orders != null && x.Orders.Any(y => y.OrderItems != null && y.OrderItems.Any(z => z.Quantity == 1)));
customers2.ToList().ForEach(x =>
{
x.Orders.ForEach(y =>
{
y.OrderItems.RemoveAll(z => z == null || z.Quantity != 1);
});
x.Orders.RemoveAll(y => y == null || y.OrderItems.Count == 0);
});
return customers2;

This will get all customers with the specific orders where the order items quantity is the desired amount.
To use this it will remove all orderitems that do not have one item quantity. So you need to clone the list before using this function.
public static List<Customer> GetCustomersWithOrderItemQuantity(List<Customer> customers, int quantity)
{
var customers2 = customers.TakeWhile(c => c.Orders.Any(o => o.OrderItems.Any(oi => oi.Quantity == quantity))).ToList();
customers2.ForEach(cust => cust.Orders.ForEach(o => o.OrderItems.RemoveAll(oi => oi.Quantity != quantity)));
return customers2;
}
You can use like this to input a specific quantity.
var customers2 = GetCustomersWithOrderItemQuantity(customers, 1);
If you want all orders where at least one item has quantity of 1 then use this.
public static IEnumerable<Customer> GetCustomersWithOrderItemQuantity(List<Customer> customers, int quantity)
{
return customers.TakeWhile(c => c.Orders.Any(o => o.OrderItems.Any(oi => oi.Quantity == quantity)));
}
The above can be used the same as the other one but will show all orders with at least one order item quantity of 1 in your example above.