Thinking about complete grids

hadley · Mar 12, 2013 · b1e2a3a · b1e2a3a
1 parent d74154c
commit b1e2a3a
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diff --git a/R/condensed.r b/R/condensed.r
@@ -37,6 +37,7 @@ condensed <- function(groups, grouped, summary) {
   for (i in seq_along(groups)) {
     attr(grouped[[i]], "width") <- groups[[i]]$width()
     attr(grouped[[i]], "origin") <- groups[[i]]$origin()
+    attr(grouped[[i]], "nbins") <- groups[[i]]$nbins()
   }
 
   names(summary) <- paste0(".", names(summary))

diff --git a/R/smooth.r b/R/smooth.r
@@ -69,3 +69,14 @@ smooth <- function(x, h, var = summary_vars(x)[1], grid = NULL, type = "mean",
   out[[var]] <- z
   structure(out, class = c("condensed", class(out)))
 }
+
+complete_grid <- function(df) {
+  stopifnot(is.data.frame(df))
+
+  breaks <- function(width, origin, nbins) {
+    origin + width * seq.int(nbins)
+  }
+
+  cols <- lapply(df, function(x) do.call(breaks, attributes(x)))
+  expand.grid(cols, KEEP.OUT.ATTRS = FALSE)
+}