#ienumerable

Difference between IEnumerable and IQueryable in C# with example. http://www.webcodeexpert.com/2017/05/difference-between-ienumerable-and.html

Resolved: Howto: Count the items from a IEnumerable without iterating? #dev #computers #programming

Howto: Count the items from a IEnumerable<T> without iterating?

private IEnumerable<string> Tables { get { yield return "Foo"; yield return "Bar"; } }

Let’s say I want iterate on those and write something like processing #n of #m. Is there a way I can find out the value of m without iterating before my main iteration?

I hope I made myself clear.

Answer [by JesperE]: Howto: Count the items from a…

How-to: Passing a single item as IEnumerable #development #programming #answer

Passing a single item as IEnumerable<T>

Is there a common way to pass a single item of type T to a method which expects an IEnumerable<T> parameter? Language is C#, framework version 2.0.

Currently I am using a helper method (it’s .Net 2.0, so I have a whole bunch of casting/projecting helper methods similar to LINQ), but this just seems silly:

public static class IEnumerableExt { // usage:…

Answer: How can I add an item to a IEnumerable collection? #development #answer #programming

How can I add an item to a IEnumerable<T> collection?

My question as title above. For example,

IEnumerable<T> items = new T[]{new T("msg")}; items.ToList().Add(new T("msg2"));

but after all it only has 1 item inside.

Can we have a method like items.Add(item)?

like the List<T>

Answer [by pb.]: How can I add an item to a IEnumerable<T> collection?

No the IEnumerable doens’t support adding items…

Fixed IEnumerable vs List – What to Use? How do they work? #dev #it #asnwer

IEnumerable vs List – What to Use? How do they work?

I have some doubts over how Enumerators work, and LINQ. Consider these two simple selects:

List<Animal> sel = (from animal in Animals join race in Species on animal.SpeciesKey equals race.SpeciesKey select animal).Distinct().ToList();

or

IEnumerable sel = (from animal in Animals join race in Species on animal.SpeciesKey equals race.SpeciesKey…

Fixed What is the difference between IQueryable and IEnumerable? #dev #it #asnwer

What is the difference between IQueryable<T> and IEnumerable<T>?

What is the difference between IQueryable<T> and IEnumerable<T>?

See also What’s the difference between IQueryable and IEnumerable that overlaps with this question.

Answer: What is the difference between IQueryable<T> and IEnumerable<T>?

The primary difference is that the LINQ operators for IQueryable<T> take Expressionobjects…

Fixed LINQ equivalent of foreach for IEnumerable #dev #it #asnwer

LINQ equivalent of foreach for IEnumerable<T>

I’d like to do the equivalent of the following in LINQ, but I can’t figure out how:

IEnumerable<Item> items = GetItems(); items.ForEach(i => i.DoStuff());

What is the real syntax?

Answer: LINQ equivalent of foreach for IEnumerable<T>

There is no ForEach extension for IEnumerable; only for List<T>. So you could do

items.ToList().ForEach(i =>…

Fixed Returning IEnumerable vs IQueryable #dev #it #asnwer

Returning IEnumerable<T> vs IQueryable<T>

What is the difference between returning IQueryable<T> vs IEnumerable<T>?

IQueryable<Customer> custs = from c in db.Customers where c.City == "<City>" select c; IEnumerable<Customer> custs = from c in db.Customers where c.City == "<City>" select c;

Will both be deferred execution and when should one be preferred over the other?

Answer: Returning…