LinQ optimization
- by Budda
Here is a peace of code:
void MyFunc(List<MyObj> objects)
{
MyFunc1(objects);
foreach( MyObj obj in objects.Where(obj1=>obj1.Good))
{
// Do Action With Good Object
}
}
void MyFunc1(List<MyObj> objects)
{
int iGoodCount = objects.Where(obj1=>obj1.Good).Count();
BeHappy(iGoodCount);
// do other stuff with 'objects' collection
}
Here we see that collection is analyzed twice and each time the value of 'Good' property is checked for each member: 1st time when calculating count of good objects, 2nd - when iterating through all good objects.
It is desirable to have that optimized, and here is a straightforward solution:
before call to MyFunc1 makecreate an additional temporary collection of good objects only (goodObjects, it can be IEnumerable);
get count of these objects and pass it as an additional parameter to MyFunc1;
in the 'MyFunc' method iterate not through 'objects.Where(...)' but through the 'goodObjects' collection.
Not too bad approach (as far as I see), but additional parameter is required to be passed.
Question: is there any LinQ out-of-the-box functionality that allows any caching during 1st Where().Count(), remembering a processed collection and use it in the next iteration?
Any thoughts are welcome.
Thanks.
