Difference b/w a!dataSubset() and todatasubset()

One just simply converts the data into a subset while the other constructs it. No difference in their output. a!datasubset() gives you access to some more properties like identifiers etc. 

Did you read the documentation before posting here? Do you have any specific question that goes beyond the documentation?

Hi Ganesh, both the functions are quite similar. To look better into each of them with examples here is the link you can follow:-
https://docs.appian.com/suite/help/23.2/fnc_system_a_datasubset.html :- a!dataSubset()
https://docs.appian.com/suite/help/23.2/fnc_scripting_todatasubset.html :- todatasubset()