I would be be grateful for any help with my query.

I have the following variables chd002_9 chd002_09 sti002_9 sti002_09 pad002_9 pad002_09…….
I have about 40 variables which I would like to use to generate new variables.

For each variable with the same prefix (1st 3 letters) I want to do the following:

1. I want to generate a new variable which uses the 1st three letters of the original variable and add “_qof” at the end for example: chd_qof pad_qof sti_qof
2. Variables ending in _9 correspond to years 2013 & 2014 while those ending in _09 correspond to years 2015 &2016
3. For variables ending in _09 I want to multiply by 100

If I were doing each variable in turn, the code would look like this:

gen chd_qof = .
replace chd_qof = chd002_9 if year ==2013
replace chd_qof = chd002_9 if year ==2014
replace chd_qof = chd002_09 *100 if year ==2015
replace chd_qof = chd002_09*100 if year ==2016

Although, I have some experience with loops, I have no idea where to start with this one. Any help would be greatly appreciated.