Linq – What is the quickest way to find out deferred execution or not?

by

Generally methods that return a sequence use deferred execution:

IEnumerable<X> ---> Select ---> IEnumerable<Y>

and methods that return a single object doesn’t:

IEnumerable<X> ---> First ---> Y

So, methods like Where, Select, Take, Skip, GroupBy and OrderBy use deferred execution because they can, while methods like First, Single, ToList and ToArray don’t because they can’t.

There are also two types of deferred execution. For example the Select method will only get one item at a time when it’s asked to produce an item, while the OrderBy method will have to consume the entire source when asked to return the first item. So, if you chain an OrderBy after a Select, the execution will be deferred until you get the first item, but then the OrderBy will ask the Select for all the items.

More Related Contents:

  1. Prevent duplicates from array, based on condition [closed]
  2. Linq: help me to make this work
  3. Get all checked nodes of a treeview
  4. How to flatten tree via LINQ?
  5. When to use .First and when to use .FirstOrDefault with LINQ?
  6. Using LINQ to remove elements from a List
  7. printing all contents of array in C#
  8. What guarantees are there on the run-time complexity (Big-O) of LINQ methods?
  9. Convert string[] to int[] in one line of code using LINQ
  10. LINQ – Left Join, Group By, and Count
  11. Extension methods must be defined in a non-generic static class
  12. Func with out parameter
  13. LINQ: Not Any vs All Don’t
  14. How to check if IEnumerable is null or empty?
  15. C# – code to order by a property using the property name as a string [duplicate]
  16. Can I specify my explicit type comparator inline?
  17. What is the Efficiency and Performance of LINQ and Lambda Expression in .Net?
  18. LINQ Inner-Join vs Left-Join
  19. DISTINCT() and ORDERBY issue
  20. Can I split an IEnumerable into two by a boolean criteria without two queries?
  21. Can I LINQ a JSON?
  22. Linq style “For Each” [duplicate]
  23. How to sort a dictionary by key
  24. Issues Doing a String Comparison in LINQ
  25. Keep Getting ‘The LINQ expression node type ‘Invoke’ is not supported in LINQ to Entities’ Exception
  26. Expressing recursion in LINQ
  27. C# Searching for files and folders except in certain folders
  28. Linq where column == (null reference) not the same as column == null
  29. Does “foreach” cause repeated Linq execution?
  30. Can I use Linq’s Except() with a lambda expression comparer?

Leave a Comment