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I have an ICollection of Thing. Thing has a string property Name. I would like to get an array of all Name in my ICollection. I know I can do this by iterating over the collection and building the array, but is there a neater way to do this with lambda notation?

It'sNotALie.
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tacos_tacos_tacos
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1 Answers1

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Sure, LINQ lets you do this very easily:

string[] names = things.Select(x => x.Name).ToArray();

Of course if you're just going to iterate over it, you don't need the ToArray part:

IEnumerable<string> names = things.Select(x => x.Name);

Or you could create a List<string> with ToList:

List<string> names = things.Select(x => x.Name).ToList();

In all of these cases you could use var instead of explicitly declaring the variable type - I've only included the type here for clarity.

Using ToList can be very slightly more efficient than using ToArray, as the final step in ToArray involves copying from a possibly-oversized buffer to a right-sized array.

EDIT: Now we know you really do need an array, it would be slightly more efficient to do this yourself with a manual loop, as you know the size beforehand. I'd definitely use the first form until I knew it was a problem though :)

Jon Skeet
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  • Thanks - the reason I want an array of string is to implement the method `GetRolesForUser` for my `RoleProvider` ... I'm not anticipating any big arrays being returned – tacos_tacos_tacos Jun 01 '13 at 17:05
  • @tacos_tacos_tacos: Right - if you definitely want a string array, then the first one is what you're after. – Jon Skeet Jun 01 '13 at 17:06