Question

What is the fastest way to convert a String into an array of Short integers representing the character codes?

I am now using this but it can probably be much faster:

Dim shortsarray(mystring.Length - 1) as Short
For i As Integer = 0 To mystring.Length - 1
  shortsarray(i) = AscW(mystring.Chars(i))
Next

Thanks.

Answer 1

Dim shortsarray(mystring.Length - 1) as Short //One calculation
For i As Integer = 0 To mystring.Length - 1   //One calculation, repeats n times
  shortsarray(i) = AscW(mystring.Chars(i))    //Three calculations, repeats n times
Next

As a result, this should run in O(3n+1), or O(n). This is linear on the length of the input, and there isn’t much improvement you can expect from that since you’re doing a character-wise conversion. I think this is probably as good as you can expect, though there may be a library that will just convert the whole word in one go, making your code cleaner.

If you need performance increases, you want to first profile your whole program. This snippet may not be the problem.