public void Linq004()
{
var result = this.dataSource.Customers
.Select(cust => $"{cust.CompanyName} is client since {(cust.Orders.Any() ? cust.Orders.Min(order => order.OrderDate).ToString("MMMM yyyy") : "never")}");
LinqSamples.Show(result);
}
public void Linq006()
{
var result = this.dataSource.Customers
.Where(cust => string.IsNullOrWhiteSpace(cust.PostalCode) ||
cust.PostalCode.Any(c => !char.IsDigit(c)) ||
string.IsNullOrWhiteSpace(cust.Region) ||
!cust.Phone.StartsWith("(", StringComparison.InvariantCultureIgnoreCase))
.Select(cust => $"Customer {cust.CompanyName} have postal code {cust.PostalCode}, region {cust.Region}, phone {cust.Phone}");
LinqSamples.Show(result);
}
public void Linq005()
{
var result = this.dataSource.Customers
.Where(cust => cust.Orders.Any())
.ToDictionary(cust => cust,
cust => cust.Orders.OrderBy(order => order.OrderDate).FirstOrDefault())
.OrderBy(kvp => kvp.Value.OrderDate.Year)
.ThenBy(kvp => kvp.Value.OrderDate.Month)
.ThenByDescending(kvp => kvp.Key.Orders.Sum(order => order.Total))
.ThenBy(kvp => kvp.Key.CompanyName)
.Select(dict => $"{dict.Key.CompanyName} is client since {dict.Value.OrderDate.ToString("yyyy MMMM")}, total is {dict.Key.Orders.Sum(order => order.Total)}");
LinqSamples.Show(result);
}
public void Linq001()
{
int[] arr = { 100, 1000, 10000, 100000 };
foreach (var x in arr)
{
LinqSamples.WriteHeader($"x is {x}");
var products = this.dataSource.Customers
.Where(cust => cust.Orders.Sum(order => order.Total) > x)
.Select(cust => $"Name = {cust.CompanyName}, Order's total price = {cust.Orders.Sum(order => order.Total)}");
LinqSamples.Show(products);
}
}
public void Linq002()
{
var сustomers = this.dataSource.Customers;
var suppliers = this.dataSource.Suppliers;
var result =
from supplier in suppliers
from customer in сustomers
where supplier.Country == customer.Country &&
supplier.City == customer.City
select $"Company {customer.CompanyName} and supplier {supplier.SupplierName} are in the same city {supplier.City} and country {supplier.Country}";
LinqSamples.WriteHeader("Ingroupped");
LinqSamples.Show(result);
var grouppedResult =
from grouppedCollection in (
from supplier in suppliers
from customer in сustomers
where supplier.Country == customer.Country &&
supplier.City == customer.City
select new
{
Customer = customer,
Supplier = supplier,
})
group grouppedCollection by grouppedCollection.Customer.Country;
LinqSamples.WriteHeader("Groupped");
if (grouppedResult.Any())
{
foreach (var p in grouppedResult)
{
ObjectDumper.Write($"In {p.Key} there's");
foreach (var item in p)
{
ObjectDumper.Write($" company {item.Customer.CompanyName} and supplier {item.Supplier.SupplierName}");
}
}
}
else
{
Console.WriteLine("No such objects");
}
}
public void Linq007()
{
var result =
from product in this.dataSource.Products
group product by product.Category
into groupedByCategoryProducts
select
new KeyValuePair <string, IEnumerable <KeyValuePair <decimal, IEnumerable <Product> > > >(
groupedByCategoryProducts.Key,
from p in groupedByCategoryProducts
group p by p.UnitsInStock
into asd
select new KeyValuePair <decimal, IEnumerable <Product> >(asd.Key, asd.OrderBy(a => a.UnitPrice)));
LinqSamples.Show(result);
}
public void Linq010()
{
var clients = this.dataSource.Customers;
LinqSamples.WriteHeader("Mounthly");
var mounthly =
from order in clients.SelectMany(client => client.Orders).Select(o => o.OrderDate)
group order by order.Month
into groupped
select
new KeyValuePair <string, int>(
CultureInfo.CurrentCulture.DateTimeFormat.GetMonthName(groupped.Key),
groupped.Count());
this.Show(mounthly);
LinqSamples.WriteHeader("Yearly");
var yearly = from order in clients.SelectMany(client => client.Orders).Select(o => o.OrderDate)
group order by order.Year
into groupped
select
new KeyValuePair <int, int>(groupped.Key,
groupped.Count());
LinqSamples.Show(yearly.OrderBy(g => g.Key));
LinqSamples.WriteHeader("Bothly");
var bothly = from order in clients.SelectMany(client => client.Orders).Select(o => o.OrderDate)
group order by new { year = order.Year, mounth = order.Month }
into groupped
select
new
{
Key = new KeyValuePair <int, int>(groupped.Key.year, groupped.Key.mounth),
Value = groupped.Count(),
};
foreach (var item in bothly.OrderBy(g => g.Key.Key).ThenBy(g => g.Key.Value))
{
ObjectDumper.Write($"{item.Key.Key}, {CultureInfo.CurrentCulture.DateTimeFormat.GetMonthName(item.Key.Value)} - {item.Value}");
}
}
public void Linq003()
{
int[] arr = { 100, 1000, 10000, 100000 };
foreach (var x in arr)
{
ObjectDumper.Write("");
ObjectDumper.Write("");
ObjectDumper.Write($"x is {x}");
ObjectDumper.Write("");
ObjectDumper.Write("");
var result = this.dataSource.Customers
.Where(cust => cust.Orders.Any(order => order.Total > x))
.Select(cust => $"Customer {cust.CompanyName} have order with {cust.Orders.First(order => order.Total > x).Total} total");
LinqSamples.Show(result);
}
}
public void Linq008()
{
const int min = 10;
const int max = 100;
var dict = new Dictionary <string, uint>
{
{ "Low", 0 },
{ "Middle", 1 },
{ "High", 2 },
};
var result = this.dataSource.Products
.GroupBy(product => LinqSamples.GetRange(product, min, max),
product => $"Name = {product.ProductName}, price is {product.UnitPrice.ToString(".##")}")
.OrderBy(kvp => dict[kvp.Key]);
LinqSamples.Show(result);
}
public void Linq009()
{
var profitability = from customer in this.dataSource.Customers
group customer by customer.City
into groupped
select
new KeyValuePair <string, decimal>(groupped.Key,
groupped.SelectMany(c => c.Orders).Average(o => o.Total));
LinqSamples.WriteHeader("Profitability");
LinqSamples.Show(profitability);
var intensity = from customer in this.dataSource.Customers
group customer by customer.City
into groupped
select
new KeyValuePair <string, double>(groupped.Key, groupped.Average(customer => customer.Orders.Length));
LinqSamples.WriteHeader("Intensity");
LinqSamples.Show(intensity);
}
