Passing Unevaluated Functions as Arguments with Linq

09 April 2013

Passing Unevaluated Functions as Arguments with Linq

I was pleased with this bit of code today:

  List myList = new List{"test","monkey"};
  string[] animals = new string[]{"giraffe","goat","monkey"};
  IEnumerable reduced = myList.Where(item => animals.Any(item.Contains)).ToList();
  
  //Returns "monkey"

Filtering a list using items from another list would usually require a developer to use a nested foreach. I’m a big fan of linq for its consise syntax, readability and the functional aspects. The System.Linq .Any() extension method here has parameters IEnumarable and Predicate, however the first argument can be waived if you are passing an unevaluated predicate function.

I was doing some programming for the local zoo today, of course!