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DarthVader
DarthVader

Reputation: 55122

What is the difference between Directory.EnumerateFiles vs Directory.GetFiles?

What is the difference between Directory.EnumerateFiles vs GetFiles?

Obviously one returns an array and the other return Enumerable.

Anything else?

Upvotes: 185

Views: 69853

Answers (3)

Henk Holterman
Henk Holterman

Reputation: 273844

EnumerateFiles returns IEnumerable<string> and that implies deferred execution. It is only available in .net 4 and up.

As the File system is notoriously slow (especially for large folders) the deferred execution can be a real bonus for sequential processing. Depending on lots of other factors.

Upvotes: 39

Daniel DiPaolo
Daniel DiPaolo

Reputation: 56428

From the docs:

The EnumerateFiles and GetFiles methods differ as follows: When you use EnumerateFiles, you can start enumerating the collection of names before the whole collection is returned; when you use GetFiles, you must wait for the whole array of names to be returned before you can access the array. Therefore, when you are working with many files and directories, EnumerateFiles can be more efficient.

So basically, EnumerateFiles returns an IEnumerable which can be lazily evaluated somewhat, whereas GetFiles returns a string[] which has to be fully populated before it can return.

Upvotes: 209

Skotte
Skotte

Reputation: 324

When using EnumerateFiles, all speed is lost if you are then using .Last. This makes sense of course, because to get to the last file, it will need to enumerate all files, then grab the last one.

However, using .First or .FirstOrDefault becomes very fast, because it simply grabs the first item and moves on.

Upvotes: 19

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