Creating a loop to add a prefix to a variable

[Robert Wishart]

Hi,

I'm trying to create a loop to add a two letter prefix (e.g. AB) to a varlist I've merged into a dataset so I know that they weren't part of the original data.

Does anyone have any ideas on how I could create a loop that would change varname to AB_varname for the whole list without easily? I've seen various posts about loops for renaming variables but they all seem to involve numbers

Thanks

Robert

[Attaullah Shah]

Try this

foreach v of varlist _all{
ren `v' AB_`v'
}

[daniel klein]

No loops needed since Stata 12.

rename (*) (AB_*)

Best
Daniel

[Robert Wishart]

Thanks, I'm a little confused as to what v refers to - is it a macro that I need to assign?

Robert

[Jorrit Gosens]

It is the name of the local macro that gets assigned in that first line of the foreach block, see also the guide: http://www.stata.com/manuals13/pforeach.pdf
You can use whatever name. e.g.,:

foreach my_intuitive_local_name of varlist _all{
ren `my_intuitive_local_name' AB_`my_intuitive_local_name'
}

However, as Daniel noted; no need for a loop.

[Sanika Rr]

Hello All,
I am using Stata 16
I tried using the below code for creating a prefix to my 30 variables

foreach x of varlist catcurrentpolicieswarminglevel- ngfsdelayed2âc25thpercentile {
 rename `x' atmp_`x'
 }

However I am getting the following error message
1 new variable name invalid
You attempted to rename catcurrentpolicieswarminglevel to atmp_catcurrentpolicieswarminglevel. That is an invalid Stata variable name.

Edit: I did use

ren * x*

and I still get the same error message.

Kindly suggest what I may be doing wrong here? Grateful for any help!

[Nick Cox]

Stata variable names are at most 32 characters long.

. di strlen("atmp_catcurrentpolicieswarminglevel")
35

help varname explains. So, loop or no loop, the problem is the same.

[Sanika Rr]

Thank you, Sir. I fixed it.