The main issue is the delimiters you are using for the INDEXW() function. Since the digit string is right before the extension the right hand delimiter there is a period instead of an underscore.
So you really just need to add period along with underscore in the list of delimiters in this function call.
indexw(filename,scan("&lh_rb.",i,","),"_.")
Here is a simpler version of what I think you are doing that takes advantage the you have the FUNCTION_COMPONT macro variable which can be used to select the right list. Although I suspect that your real problem is different that what the code you posted is doing. I thought you wanted to be able to route files to more than one target directory at a time? With the current logic you would want to run the filtering step twice, once with FUNCTION_COMPONT=LH and then another run with FUNCTION_COMPONT=NL to move those files.
%let inpath=/var/sasdata/INPUT/GT;
%let lh_path=/var/sasdata/INPUT/LH;
%let nl_path=/var/sasdata/INPUT/NL;
%let nl_rb=0012,5678,9012;
%let lh_rb=0012,5678,9012;
%let function_compont=LH;
* Get list of files in source directory ;
filename source "&inpath";
data files ;
length id 8 msg filename $256 ;
did=dopen("source");
if did<=0 then do;
msg=sysmsg();
put msg;
stop;
end;
do id=1 to dnum(did);
filename=dread(did,id);
output;
end;
did=dclose(did);
drop did msg;
run;
* Generate list of files to move ;
data files_to_move ;
set files ;
length extension $10 source target $256 ;
* Get extension on the filename ;
if index(filename,'.') then extension=lowcase(scan(filename,-1,'.')) ;
* only keep csv or xlsx files ;
if extension in ('csv','xlsx');
/* Check if any of the words in ..._RB string exist in the filename */
length flag 8 words $500 ;
flag = 0;
words = symget("&function_compont._rb");
do i = 1 to countw(words,",") while(not flag);
if indexw(filename,scan(words,i,","),"_.") then flag = 1;
end;
if flag then do;
target = catx('/',"&&&function_compont._path",filename);
source = catx('/',"&inpath",filename);
end;
drop i words ;
run;
Once the step to get the list is separated from the step to filter and calculate source and target you can now test that second step with some simulated filename data.
data files ;
length id 8 filename $256 ;
id+1;
input filename ;
cards;
IFR_GT_MS_0012.xlsx
IFR_GT_TR_1_0012_1_20201009T075212.csv
someotherfile.pdf
IFR_GT_MS_0099.xlsx
;
Here is output for that list of files.
Obs id filename extension
1 1 IFR_GT_MS_0012.xlsx xlsx
2 2 IFR_GT_TR_1_0012_1_20201009T075212.csv csv
3 4 IFR_GT_MS_0099.xlsx xlsx
Obs source
1 /var/sasdata/INPUT/GT/IFR_GT_MS_0012.xlsx
2 /var/sasdata/INPUT/GT/IFR_GT_TR_1_0012_1_20201009T075212.csv
3
Obs target flag
1 /var/sasdata/INPUT/LH/IFR_GT_MS_0012.xlsx 1
2 /var/sasdata/INPUT/LH/IFR_GT_TR_1_0012_1_20201009T075212.csv 1
3 0
