QS Informatica - Manuale LUALua Standard LibraryString Manipulation Library strsub strsub strsub (S, I [, J]) Returns another string,which is a substring of S, starting at I and running until J; I and Jmay be negative. The default value of J is -1 (the end.) strsub(s,1,j) returns a preflx; strsub(s, -i) returns a sufflx.