what is the most efficient way of turning the list of values of a dictionary into an array
for example, if i have:
Dictionary where key is string and value is Foo
i want to get Foo[]
I am using VS 2005, C# 2.0
+14
A:
// dict is Dictionary<string, Foo>
Foo[] foos = new Foo[dict.Count];
dict.Values.CopyTo(foos, 0);
// or in C# 3.0:
var foos = dict.Values.ToArray();
Matt Hamilton
2008-10-13 09:05:08
Does the extension .ToArray<Foo>() perform any better?
Goran
2008-10-13 09:15:56
but how do we know that it's the most efficient ?
Tom Carter
2008-10-13 09:16:55
I can't see how ToArray() could be any faster than the straight copy - which seems to be minimalistic.
Samuel Kim
2008-10-13 09:18:14
@Tom I usually take the view that anything built into the framework (like .CopyTo() or .ToArray()) is the most efficient way to do it. The Microsofties are smarter than me. :)
Matt Hamilton
2008-10-13 09:56:04
ToArray is less performant than CopyTo (it uses CopyTo to copy to an internal intermediate representation, and then Copy again to return it out). However, as with all micro-performance related matters go for readability, robustness and maintainability and measure performance if it's an issue.
ICR
2008-10-13 14:01:47
+3
A:
There is a ToArray() function on Values:
Foo[] arr = new Foo[dict.Count];
dict.Values.CopyTo(arr, 0);
But I don't think its efficient (I haven't really tried, but I guess it copies all these values to the array). Do you really need an Array? If not, I would try to pass IEnumerable:
IEnumerable<Foo> foos = dict.Values;
Grzenio
2008-10-13 09:09:43