Have a number of product names with sizes in.

For example "X 300g", "X 400 g", "X 250 kg", "X 25kg".

Now I would like to replace all instances of "NumberUnit" with "Number Unit", i.e. "300g" to "300 g", "25kg" to "25 kg", etc.

I know I can do that easily with a loop and a string replace, but there are millions of products and I worry it would take to long to do it that way.

Instead, I guess it might be a better idea to do a Regex.Replace() on each product name.

Agree? - and how would you write the regex?

Thanks.