Also clarify how fill= works in locf

Author: MichaelChirico

man/nafill.Rd

@@ -16,7 +16,7 @@ setnafill(x, type=c("const","locf","nocb"), fill=NA, nan=NA, cols=seq_along(x))
 \arguments{
   \item{x}{ Vector, list, data.frame or data.table of numeric columns. }
   \item{type}{ Character, one of \emph{"const"}, \emph{"locf"} or \emph{"nocb"}. Defaults to \code{"const"}. }
-  \item{fill}{ Double or integer, value to be used to fill. }
+  \item{fill}{ Numeric value to be used to replace missing observations. See examples. }
   \item{nan}{ Either \code{NaN} or \code{NA}; if the former, \code{NaN} is treated as distinct from \code{NA}, otherwise, they are treated the same during replacement. See Examples. }
   \item{cols}{ Numeric or character vector specifying columns to be updated. }
 }
@@ -37,6 +37,10 @@ x = c(1, NA, NaN, 3, NaN, NA, 4)
 nafill(x, "locf")
 nafill(x, "locf", nan=NaN)
 
+# fill= applies to any leftover NA
+nafill(c(NA, x), "locf")
+nafill(c(NA, x), "locf", fill=0)
+
 dt = data.table(v1=x, v2=shift(x)/2, v3=shift(x, -1L)/2)
 nafill(dt, "nocb")