Generating a varlist using loops

[Daniel Perez]

Dear all,

I have several variables with a similar structure of name (i.e., ratio_XXXXXXXXXX_co_LLL, where X and L are numbers). Let me mention that there are variables with the same XXXXXXXXXX number but different LLL, and the comment is also valid in reverse. I need to define a varlist of all these variables.
Is it possible to define the varlist using a loop instead of doing it manually?

Thanks!

[eric_a_booth]

No need for a loop. Take a look at the help files for 'varlist', 'unab', and 'ds' for ideas on how to build these types of lists. (also I'm not sure what the phrase " the comment is also valid in reverse " refers to but note that the asterisk wildcard does not need to know how many characters are in the XXXXX or LLL parts)

examples:

unab test: ratio_*_co_*
di `"`test'"'

ds ratio_*_co_* 
loc test2 `r(varlist)'
di `"`test2'"'

[Daniel Perez]

Thank you, Eric, I will follow your advice!

[Daniel Perez]

Dear Eric and colleagues,

I found the suggestion very useful. However, I have another related question. I would need to build a list of just all the variables with equal XXXXXXXXXX part (variables are named as ratio_XXXXXXXXXX_co_LLL, where X and L are numbers). For example, I would like to build a varlist of only those variables with ratio_11111111112_co_LLL for all LLL numbers. The problem is that I have more than 3000 categories of XXXXXXXXXX, so it is not a reasonable solution to type every ten digits individually. The ds command works great, but I do not know how to use it here (maybe I should require a previous loop?)

ratio_11111111112_co_001
ratio_11111111112_co_005
ratio_11111111112_co_007
ratio_11111111112_co_010
ratio_11111111112_co_015
ratio_11111111112_co_025

Thanks for the time to read this post.

[Nick Cox]

I am not sure if I understand but (e.g.)

ratio_?????????2_co_???

and

ratio_??????????_co_???

and

ratio_*_co_???

might all be useful as wildcards.