Linq Expression for All Objects With Lowest Cost

[Aeden Jameson]

Suppose I have the class foo

class Foo
{
PropertyOne;
PropertyTwo;
}

and I have a cost calculator class that uses lots of different
information to
calculate a cost.

class CostCalculator
{
public decimal Calculate(Foo foo);
}


I'm struggling with how one would write a linq expression to select
all objects that have the lowest cost. There's no guarantee of
uniqueness. Thanks for your help.

Cheers,
Aeden

 

[Andrey Dudarev]

First you need create collection or IEnumerable of Foo objects:

List<Foo> Foos = GetFoos(....);

,then

CostCalculator calculator = new CostCalculator ();
var minCost = Foos.Min( s=> calculator(s)).FirstOrDefault();




Aeden Jameson wrote:

Linq Expression for All Objects With Lowest Cost
12-Apr-10

Suppose I have the class fo

class Fo

PropertyOne
PropertyTwo


and I have a cost calculator class that uses lots of differen
information t
calculate a cost

class CostCalculato

public decimal Calculate(Foo foo)


I am struggling with how one would write a linq expression to selec
all objects that have the lowest cost. There is no guarantee o
uniqueness. Thanks for your help

Cheers
Aeden

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[Andrey Dudarev]

List<Foo> foos = ... method to create a collection of Foos...

CostCalculator calc = new CostCalculator();
IEnumerable<Foo> minCosts = foos.Min( s=> calc(s));



Aeden Jameson wrote:

Linq Expression for All Objects With Lowest Cost
12-Apr-10

Suppose I have the class fo

class Fo

PropertyOne
PropertyTwo


and I have a cost calculator class that uses lots of differen
information t
calculate a cost

class CostCalculato

public decimal Calculate(Foo foo)


I am struggling with how one would write a linq expression to selec
all objects that have the lowest cost. There is no guarantee o
uniqueness. Thanks for your help

Cheers
Aeden

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[Peter Duniho]

Suppose I have the class foo

class Foo
{
PropertyOne;
PropertyTwo;
}

and I have a cost calculator class that uses lots of different
information to
calculate a cost.

class CostCalculator
{
public decimal Calculate(Foo foo);
}


I'm struggling with how one would write a linq expression to select
all objects that have the lowest cost. There's no guarantee of
uniqueness. Thanks for your help.

I don't know that there would be code that is expressible solely as a
LINQ expression and which would do that. However, you can certainly
take advantage of LINQ to do something like that.

For example:

IEnumerable<Foo> data = …;
CostCalculator calc = …;

var ordered = from foo in data
select new { Foo = foo, Cost = calc.Calculate(foo) }
orderby Cost;

decimal minCost = ordered.First().Cost;

var least = from fooAndCost in ordered
where fooAndCost.Cost == minCost
select fooAndCost.Foo;

There are other ways you might accomplish the same thing using LINQ, but
the above should work and isn't too inefficient.

If the above doesn't address your question, you should try to be more
specific.

Pete

 

[yogendrasinh]

yes you are near... here is how it should work


List<Foo> foos = ... method to create a collection of Foos...

CostCalculator calc = new CostCalculator();
IEnumerable<Foo> minCosts = foos.Min( s=> calc.Calculate(s));