Positions / PendingOrders .Count & .Find - Inconsistency

amusleh
24 Jan 2022, 09:16 ( Updated at: 25 Jan 2022, 10:18 )

Hi,

The Find and FindAll methods are only available on Positions, it's basically a shorthand version of Linq where extension method:

var myPositions = Positions.Find("myLabel");
// Is equivalent to
var myPositions = Positions.Where(position => position.Label == "myLabel");
// Note: Don't use == for string equality as it will use the current thread culture,
// instead use Equal method of string and set the type of comparison you are looking
// to do, personally I prefer to use
  var myPositions = Positions.Where(position => position.Label.Equals("MyLabel", StringComparison.OrdinalIgnoreCase));
// which is both case insensitive and has much better performance

Now regarding PendingOrders, you can use Linq here too, no need for any extra helper methods:

var myOrders = PendingOrders.Where(order => order.Label.Equals("MyLabel", StringComparison.OrdinalIgnoreCase));

And don't forget to call "ToArray" at the end:

var myPositions = Positions.Where(position => position.Label.Equals("MyLabel", StringComparison.OrdinalIgnoreCase)).ToArray();
var myOrders = PendingOrders.Where(order => order.Label.Equals("MyLabel", StringComparison.OrdinalIgnoreCase)).ToArray();

Otherwise anytime you iterate over it a new allocation will be made and the Linq query will be executed several times.

The Find/FindAll methods are added only to make things little bit easier for those who have no knowledge of .NET or Linq, but I strongly recommend you to use Linq.

ncel01
24 Jan 2022, 21:38

RE:

amusleh said:

Hi,

The Find and FindAll methods are only available on Positions, it's basically a shorthand version of Linq where extension method:

var myPositions = Positions.Find("myLabel");
// Is equivalent to
var myPositions = Positions.Where(position => position.Label == "myLabel");
// Note: Don't use == for string equality as it will use the current thread culture,
// instead use Equal method of string and set the type of comparison you are looking
// to do, personally I prefer to use
  var myPositions = Positions.Where(position => position.Label.Equals("MyLabel", StringComparison.InvariantCultureIgnoreCase));
// which is both case insensitive and has much better performance

Now regarding PendingOrders, you can use Linq here too, no need for any extra helper methods:

var myOrders = PendingOrders.Where(order => order.Label.Equals("MyLabel", StringComparison.OrdinalIgnoreCase));

And don't forget to call "ToArray" at the end:

var myPositions = Positions.Where(position => position.Label.Equals("MyLabel", StringComparison.OrdinalIgnoreCase)).ToArray();
var myOrders = PendingOrders.Where(order => order.Label.Equals("MyLabel", StringComparison.OrdinalIgnoreCase)).ToArray();

Otherwise anytime you iterate over it a new allocation will be made and the Linq query will be executed several times.

The Find/FindAll methods are added only to make things little bit easier for those who have no knowledge of .NET or Linq, but I strongly recommend you to use Linq.

Hi amusleh,

That's great.

Thanks for clarifying!