I am sorry. I am not sure if the mail a send before to this list was rejected because of header (subject). I've changed it. The first maybe was not appropriate. I did a function (sec_conop) whose arguments are syndic, well and wellconop. sec_conop(syndic='01syndic.txt',well='well-1.csv',wellconop='well-1.dat');closeAllConnections() This function takes “well” and “syndic”, matching between them and then it does some transformations. The result is exported to “wellconop”. I will apply this function to one hundred different “wells”. Therefore, for each well I use, the “wellconop argument will change too. For intance if “well” is now well-2.csv, the function will be sec_conop(syndic='01syndic.txt',well='well-2.csv',wellconop='well-2.dat');closeAllConnections() I am trying to apply this function automatically to all “well” I have, but I do not find the way. The last I tried, for three different “wells”, was : wells<-data.frame(funct=rep('sec_conop(',3),syndic=c('01syndic.txt','01syndic.txt','01syndic.txt'),well=c('well-1.csv','well-2.csv','well-3-1.csv'),wellconop=c('well-1.dat','well-2.dat','well-3.dat')) funct_3wells<-paste(wells$funct,"'",wells$syndic,"'", "," ,"'", wells$well,"'", "," , "'" ,wells$wellconop,"'",")",";","closeAllConnections()",sep='') lapply(funct_3wells,as.formula) This way works partially because the results in “wellconop” are truncated. Has anyone any suggestion? Thanks in advance Carlos ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. [[alternative HTML version deleted]]