Check for correct input in arrange/mutate/summarise

R/helper-arrange.r

@@ -23,6 +23,8 @@
 #' # Sort with displacement in descending order
 #' arrange(myCars, cyl, desc(disp))
 arrange <- function(df, ...) {
+  stopifnot(is.data.frame(df))
+
   ord <- eval(substitute(order(...)), df, parent.frame())
   if(length(ord) != nrow(df)) {
     stop("Length of ordering vectors don't match data frame size",

R/helper-mutate.r

@@ -26,6 +26,8 @@
 #' system.time(transform(baseball, avg_ab = ab / g))
 #' system.time(mutate(baseball, avg_ab = ab / g))
 mutate <- function(.data, ...) {
+  stopifnot(is.data.frame(.data) || is.list(.data) || is.environment(.data))
+
   cols <- as.list(substitute(list(...))[-1])
   cols <- cols[names(cols) != ""] # Silently drop unnamed columns
 

R/helper-summarise.r

@@ -21,6 +21,8 @@
 #'  duration = max(year) - min(year),
 #'  nteams = length(unique(team)))
 summarise <- function(.data, ...) {
+  stopifnot(is.data.frame(.data) || is.list(.data) || is.environment(.data))
+
   cols <- as.list(substitute(list(...))[-1])
 
   # ... not a named list, figure out names by deparsing call