how to extract substring and numbers only using grep/sed

Question

I have a text file containing both text and numbers, I want to use grep to extract only the numbers I need for example, given a file as follow:

miss rate 0.21          


        

Answer 1

I believe

sed 's|[^0-9]*\([0-9\.]*\)|\1 |g' fiilename

will do the trick. However every entry will be on it's own line if that is ok. I am sure there is a way for sed to produce a comma or space delimited list but I am not a super master of all things sed.