Graphing averages using collapse mean and loops with same suffix

[John Singer]

Hello,

I am trying to graph cross-country distributions along with international averages using loops.
Suppose c25 is the 25th percentile of a country's trade volume, and i25 is the international average of trade volume for that year. Same goes for c50 being the 50th percentile by country, etc. See dataexample below (numbers are made up)

* Example generated by -dataex-. For more info, type help dataex
clear
input str3 Country int Year byte(c25 i25 c50 i50 c75) double i75 int(aloc ex)
"GER" 2000  4 3  8  6 12                  9  50  85
"FRA" 2000  3 3  6  6  9                  9  20  56
"USA" 2000  2 3  4  6  6                  9  40  29
"GER" 2001  5 6 10 12 15 15.333333333333334  88  90
"FRA" 2001  6 6 12 12 18 15.333333333333334  90 100
"USA" 2001  7 6 14 12 13 15.333333333333334  89  88
"GER" 2002  8 9 16 18 24                 27 104 200
"FRA" 2002  9 9 18 18 27                 27 203 490
"USA" 2002 10 9 20 18 30                 27 194 190
end

[/CODE]

Now I'd like to have a graph with the mean, sd, 25th percentile, 50th percenile, 75th percentile, and 90th percentile across countries. To do this, I have:

putpdf clear
 putpdf begin, pagesize(letter)
  
 local varlist c25 c50 c75 aloc ex
 
 foreach v of varlist `varlist'{
     preserve
     local vlab: var lab `v'
    collapse mean = `v' (sd) sd = `v' (p25) p25 = `v' (p50) p50 = `v' (p75) p75 = `v' = `v', by(year)
    graph twoway (line mean year) (line sd year) (line p25 year) (line p50 year) (line p75 year), title("`v'") name(`v', replace)
  graph export "`v'.png", name(`v') as(png) replace
  putpdf paragraph, halign(center)
  putpdf image "`v'.png"
  restore
 }  

  putpdf save "example.pdf", replace

The above code works great and is doing what I want it to. However, what I'd like to add is a line for the international distribution for a given percentile. For example, the graph for the cross-country distribution at the 25th percentile would also show the international 25th percentile. Two variables, aloc and ex, are not distributions themselves so no international average should be graphed for them. Is there a way to include this run in the loop? Something like "if `v' ends in "25", also graph i25. if `v' ends in "50," also graph i50)

For example, if I have the code below (adding the mean of i25, then I get what I want for the 25th percentile graph, but not the other ones).

putpdf clear
putpdf begin, pagesize(letter)

local varlist c25 c50 c75 aloc ex

foreach v of varlist `varlist'{
preserve
local vlab: var lab `v'
collapse mean = `v' i25 (sd) sd = `v' (p25) p25 = `v' (p50) p50 = `v' (p75) p75 = `v' = `v', by(year)
graph twoway (line mean year) (line sd year) (line p25 year) (line p50 year) (line p75 year) (line i25 year), title("`v'") name(`v', replace)
graph export "`v'.png", name(`v') as(png) replace
putpdf paragraph, halign(center)
putpdf image "`v'.png"
restore
}

Thank you in advance and let me know if this makes sense!