Unlike other programming language such as Python and Java, R is less equipped with state of art level Integrated Development Environment. Thus, debugging program in R comes with a little trivial. Perform "Assert" in Python/C, Assert(test_expr) expression will throw out an exception if "test_expr" was false. In R , this feature can be implement with function "stopifnot()", let's demo this function via below example: demo <- function (a){ stopifnot(a < 2000) if (a < 2000){ Read more [...]