quantargo#22 - function for log-transformation is added.

R/transform_log.R

@@ -0,0 +1,20 @@
+#' transform_log
+#'
+#' log-transformation of a numeric vector. For details about log-transformation please see you basic school math textbook.
+#' @param x a numeric vector
+#' @return log-transformed vector \code{x}
+#' @examples
+#' example_vector=c(1,2,3,4,5,6,7,8,9,10)
+#' transform_log(example_vector)
+#' @export
+
+transform_log <- function(x){
+
+  if( is.null(x) )    stop("Input vector is not allowed to be NULL.")
+  if( any(is.na(x)) ) stop("There is at least one NA value in input vector.")
+  if( any(x <= 0)  )  stop("There is at least one negative value.")
+  if( any(is.numeric(x) == FALSE) )  stop("There is at least one non-numeric value.")
+  y<-log(x)
+  return(y)
+
+}