Can anyone tell me how to best possible way to convert the following code to LINQ:
static int MyMethod(MyClass my, bool b)
{
int cnt = 0;
foreach(SomeClass cls in my.SomeMethod()
{
cnt = cnt + cls.length;
}
if(b == true)
{
foreach(MyClass aa in my.SomeOtherMethod())
{
cnt = cnt + MyMethod(aa, true); // recursive
}
}
return cnt;
}
Please see that I know that the code above works fine, but I need to write it in LINQ and compare.
As Darin says, you can't easily recurse without doing so explicitly - but you can still simplify this code with LINQ:
static int MyMethod(MyClass my, bool b)
{
int cnt = my.SomeMethod().Sum(cls => cls.length);
if (b)
{
cnt += my.SomeOtherMethod().Sum(aa => MyMethod(aa, true));
}
return cnt;
}
First of all, you should use the solution by Jon, because it is the most straightforward and readable soltion you can get. However, you can write recursive Func<...> declarations in C#, so the code could be rewritten like this:
Func<MyClass, bool, int> myFoo = null;
f = (my, b) =>
my.SomeMethod().Sum(cls => cls.length) +
(b ? my.SomeOhterMethod().Sum(aa => myFoo(aa, true)) : 0);
This is essentially the same thing as what Jon posted, with the exception that I'm using Func<..> instead of a full method. (This can be useful for encoding recursion in LINQ queries, but I think it is useful only very rarely)
myFoo a value to start with - typically null - so that it's definitely assigned before the second statement. I think you meant to assign to myFoo, too :) Obviously the F# version would be somewhat neater...
null (because the C# compiler uses the current value, it will not use null during the recursive call). The F# version would be a bit simpler because F# syntax for "functions" is more lightweight, but it is essentially the same (unless you use tricks like Y combinator, but that's not very practical).You cannot write recursive queries with LINQ.
