Hello How can I set a default for the 'list.len' argument in 'str'? x <- as.data.frame(matrix(1:1000, ncol=1000)) str(x) formals(str) <- alist(object=, ...=, list.len=1000) args(str); formals(str) str(x) Does not display errors, but does not work either. Thanks for help Sören