Problem with saving graphs with wildcard in names

[Alec Wall]

Hi there!

I'm having some difficulties saving and combining graphs that I have created using a foreach loop and the mrgraph command. The problem seems to be related to the fact that I'm using a wildcard with the mrtab command, but the resulting graphs can't be saved with the "*" in their name (because I suppose it is invalid syntax).

I'm using the following code:

local Q1a1vars Q1a1_*
local Q1a2vars Q1a2_*
local mrvars `Q1a1vars' `Q1a2vars'

foreach var of local mrvars {
mrtab `var'
mrgraph hbar `var' , stat(col) name(`var')
}

where the local Q1a1vars, for example, contains Q1a1_a Q1a1_b Q1a1_c etc. (which is why I use the wildcard). mrvars is therefore a local of locals. In the actual dataset, I hope to perform this foreach loop over a total of 33 similarly constructed locals, but I'm just including two here so as to not over-complicate things.

I'm able to successfully generate the graphs using mrgraph, it's just the naming that is a problem.

Does anyone have any advice about how I could name the graphs?

Please let me know if any additional information is needed!
-Alec

[Andrew Musau]

If you simply want to remove "_*", you can define a local

foreach var of local mrvars {
     mrtab `var'
     local name = subinstr("`var'", "_*", "",.)
     mrgraph hbar `var' , stat(col) name(`name')
}

[Alec Wall]

Thanks Andrew-- that worked perfectly (and is now super obvious). Think I just needed a second set of eyes. Cheers!

[William Lisowski]

You have a fundamental problem with your code in post #1. The commands

local Q1a1vars Q1a1_* 
local Q1a2vars Q1a2_*

do not expand the variable names as you think they do, because variable name expansion only occurs where Stata is expecting a variable list.

Consider the following example based on your code, and the corrected implementation.

. describe, simple
a_1  a_2  a_3

. 
. local avars a_* 

. macro list _avars
_avars:         a_*

. 
. foreach var of local avars {
  2. list `var' in 1
  3. }

     +-----------------+
     | a_1   a_2   a_3 |
     |-----------------|
  1. |   1     2     3 |
     +-----------------+

. 
. unab avars : a_*

. macro list _avars
_avars:         a_1 a_2 a_3

. 
. foreach var of local avars {
  2. list `var' in 1
  3. }

     +-----+
     | a_1 |
     |-----|
  1. |   1 |
     +-----+

     +-----+
     | a_2 |
     |-----|
  1. |   2 |
     +-----+

     +-----+
     | a_3 |
     |-----|
  1. |   3 |
     +-----+

[Andrew Musau]

You have a fundamental problem with your code in post #1. The commands
Code:
local Q1a1vars Q1a1_* local Q1a2vars Q1a2_*
do not expand the variable names as you think they do, because variable name expansion only occurs where Stata is expecting a variable list.

I think Alec wants these to be read literally in the graph command. Consider the following:

sysuse auto, clear
tab rep78, gen(r78)
local vars r78*
gr bar `vars'