Fix documentation for ylim

The range of mtcars wt data is from 1.513 to 5.424, so the previous example was
causing an error because there were no points to obtain a range from.

Author: jimhester

R/limits.r

@@ -24,9 +24,9 @@
 #' ylim(15, 20)
 #' ylim(c(10, 20))
 #' ylim("a", "b", "c")
-#' qplot(mpg, wt, data=mtcars) + ylim(15, 20)
+#' qplot(mpg, wt, data=mtcars) + ylim(0, 4)
 #' # with automatic upper limit
-#' qplot(mpg, wt, data=mtcars) + ylim(15, NA)
+#' qplot(mpg, wt, data=mtcars) + ylim(0, NA)
 xlim <- function(...) {
   limits(c(...), "x")
 }

man/xylim.Rd

@@ -31,9 +31,9 @@ qplot(mpg, wt, data=mtcars) + xlim(NA, 20)
 ylim(15, 20)
 ylim(c(10, 20))
 ylim("a", "b", "c")
-qplot(mpg, wt, data=mtcars) + ylim(15, 20)
+qplot(mpg, wt, data=mtcars) + ylim(0, 4)
 # with automatic upper limit
-qplot(mpg, wt, data=mtcars) + ylim(15, NA)
+qplot(mpg, wt, data=mtcars) + ylim(0, NA)
 }
 \seealso{
 For changing x or y axis limits \strong{without} dropping data