Best Practices for Linq Enumerables and Queryables

Re:Best Practices for Linq Enumerables and Queryables by solutionyogi on Friday August 24, 2012 @11:36AM (#4428061)

Readability is definitely subjective. For simple scenarios, I do prefer the extension method.

E.g. in my code, it would actually be like

   var males = customers.Where(c => c.IsMale);

   var males = from c in customers where c.IsMale select c;

But often, queries are not that simple and in such scenario query syntax offers far more readability:

e.g.

   var filteredCustomers = 
                        from c in customers

                        join o in orders on o.customerid = c.customerid

                        where c.IsMale && c.Age > 30

                        where o.IsPending

                        select new {Customer = c, Order = o};

The corresponding extension method syntax will not be readable. In fact, I don't even know how to write that code off top of my head.

My point was that the whole purpose of query syntax was to improve readability and it was not about 'pretty' or 'clever'.

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Re:Best Practices for Linq Enumerables and Queryables by SimonB86 on Friday August 24, 2012 @12:47PM (#4428357)

The corresponding extension method syntax is:

  var filteredCustomers = customers
      .Join(orders,
          c => c.customerid,
          o => o.customerid,
          (c, o) => new { Customer = c, Order = o }
      )
      .Where(x => x.Customer.IsMale && x.Customer.Age > 30)
      .Where(x => x.Order.IsPending);

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Re:Best Practices for Linq Enumerables and Queryables by libria on Friday August 24, 2012 @01:43PM (#4428663)

I've used two from's for inner joins:

    var filteredCustomers =
       from c in customers
       from o in orders
       where o.customerid = c.customerid &&
             c.IsMale && c.Age > 30 &&
             o.IsPending
       select new {Customer = c, Order = o};

This is one of those cases where I'll favor query syntax over extensions. OTOH, query syntax requires an explicit `select` where it's often optional in extensions. Also, `.ToList()` doesn't have a query syntax counterpart so you'll often mix both if you tend to favor query.

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Re:Best Practices for Linq Enumerables and Queryables by redstripe on Friday August 24, 2012 @12:00PM (#4428163)

Assuming you have a foreign key set up between customers and orders, your 'order' entity will automatically have a 'customer' property so you can avoid the 'join' syntax.

If your objective is to find orders that belong to male customers over 30:

filteredCustomers = orders.Where(o => o.IsPending && o.customer.IsMale && o.customer.Age > 30);

Some more about avoiding joins (which makes it easier to use the extension syntax): http://blogs.teamb.com/craigstuntz/2010/01/13/38525/

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