Incrementing over items of a list in a loop

[Emilio Colombo]

Dear all,


I have the following problem
I have a list of files that identify countries.
In need to merge recursively each file with the remaining files in the list

For example suppose the files are defined in the file list below

local filelist "AT BE BG CY CZ DE DK"
I need to merge the first file AT recursively with the subsequent files BE BG CY CZ DE DK
Subsequently I need to merge the second file BE with the subsequent files BG CY CZ DE DK
And so forth

The problem is that I do not know how to move the index over a list which is not made by numbers
If the list is made by numbers I would increment the loop by using ++`x’

I tried using the macro `ferest()’ but for some reason it skips one position

Here an example using instead of merge

local filelist "AT BE BG CY CZ DE DK"

foreach x of local filelist {
display "`x'"
display "`ferest()'"
local filelist "`ferest()'"

}

What am I missing?
Thank you in advance

[Nick Cox]

I can only interpret the question as wanting an iteration over an expanding list of files.

merge DE DK

merge CZ DE DK

merge CY CZ DE DK

where each merge after the first is a merge of one file not seen before and another file produced by the previous merge.

If that was the real problem, I might not write a loop at all but just crank out the 7 statements needed.

But why this particular pair, triple, ... makes sense but not the others I can't follow. Why Denmark and Germany but not Denmark and Belgium, and so on?

So, I probably am not understanding the question at all, or the question is a proxy for a different real question, or both.

[Emilio Colombo]

Dear Nick

thanks for the reply. Probably my question was not sufficiently clear

Suppose I have 4 countries DE, DK, CZ, CY

I need to create 3 files (n-1 number of files)

File 1:
merge DE with DK, obtain DEDK
merge DEDK with CZ obtain DEDKCZ
merge DEDKCZ with CY obtain DEDKCZCY
save DEDKCZCY

Now drop from the list the first item (DE)

File 2:
merge DK with CZ obtain DKCZ
merge DKCZ with CY obtain DKCZCY
save DKCZCY

Now drop from the list the second item (DK)

File 3:
merge CZ with CY obtain CZCY
save CZCY

I can do it by specifying several list., however I would like to automize the process as much as possible as I have more than 50 countries

[Nick Cox]

That looks like the same question to me. But you don't need so nearly so many merges

CZ and CY

DK and (CZ and CY)

DE and (DK and CZ and CY).