Using sed between specific lines only

Question

I have this sed command for removing the spaces after commas.

 sed -e \'s/,\\s\\+/,/g\' example.txt

How can i change it that, it will make

Answer 1

sed -e '2,3!b;s/,\s\+/,/g' example.txt

This version can be useful if you later want to add more commands to process the desired lines.