Would the following:
Dim stringlist As List(Of String)
Dim stringlisthas = stringlist.Contains("thing1")
be any slower than
Dim stringlist As List(Of String)
Dim stringlisthash As New HashSet(Of String)(stringlist)
Dim stringlisthas = stringlisthash.Contains("thing1")
Is a hashset needed for contains?
Is a hashset needed for contains?
Needed? No.
Would [
List<T>.Contains] be any slower than [HashSet<T>.Contains]?
Probably. It depends on how List<T>.Contains is implemented (its probably a linear search).
I'll answer a question you didn't ask.
Does it matter?
It depends. You have to code up both, profile it, and see if it's a bottleneck in your application. If it's not, just stick with List<T>.Contains.