How to initialize a process variable of Type Group(List) ?

Question

Hi , 
 I want to initialize the variable of type Group (list). 
 My requirement , is to get all the group names (by passing some district value example : each district has 3 groups defined ) and append all to the pv of type group (list). 
 
 I used the following but getting empty result 
 
 =a!forEach(ri!deletedAMUList, 
 append( ri!groupListFordeletedAMU, 
 getgroupbyname(concat("RTRR"," ",ri!deletedAMUList[fv!index]," ","Landman")), 
 getgroupbyname(concat("RTRR"," ",ri!deletedAMUList[fv!index]," ","Geologist")), 
 getgroupbyname(concat("RTRR"," ",ri!deletedAMUList[fv!index]," ","Engineer")))) 
 
 When passing {} in group rule input in expression rule , i am getting the result.PFA

but getting empty results as ,, using this in process model at run time. 
 PFB screenshot of empty commas in pv 
 
 Thanks 
 Soujanya

aloks0189 · Answer

Hi Soujanya B I believe, you must handle null in its response, for doing this you can make the use of wherecontains() to find out the indexes of null and use remove() to delete those index values (if any) 
 Now try calling this rule in a script task and assign it to a process variable of type Group (Array) 
 Also make sure, when the result of this rule is empty, return a default group to avoid breaking the process. 
 Hope this will work for you.