From 4ec3f31847f64a88b5786aee878e3ab75ac22d23 Mon Sep 17 00:00:00 2001
From: Fernando Mayer <fernandomayer@gmail.com>
Date: Wed, 12 Aug 2015 17:33:51 -0300
Subject: [PATCH] first function
---
R/subset.drop.all.R | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
create mode 100644 R/subset.drop.all.R
diff --git a/R/subset.drop.all.R b/R/subset.drop.all.R
new file mode 100644
index 0000000..d31162e
--- /dev/null
+++ b/R/subset.drop.all.R
@@ -0,0 +1,33 @@
+##' @title Drop unused levels after subset
+##' @name subset.drop.all
+##'
+##' @description This function is designed to be used in place of
+##' \code{\link[base]{subset}} when you want to drop off all empty
+##' levels, of all factor columns in a data frame.
+##'
+##' @param x Object to be subsetted
+##' @param ... further arguments to be passed to or from other methods
+##'
+##' @details This function works exactly the same way as
+##' \code{\link[base]{subset}} but it will drop off all empty levels
+##' of all columns that are factors in \code{x}.
+##'
+##' @return An object similar to \code{x} containing just the selected
+##' rows and columns (for a data frame). Column factors that have
+##' one or more levels emptied after the subset, will have this
+##' levels droped off.
+##'
+##' @author Fernando Mayer \email{fernando.mayer@ufpr.br}
+##'
+##' @seealso \code{\link[base]{subset}}
+##'
+##' @export
+subset.drop.all <- function(x, ...){
+ if(!is.data.frame(x)) stop("'x' must be a data.frame")
+ x <- subset(x, ...)
+ factors <- which(sapply(x, class) %in% "factor")
+ for(i in factors){
+ x[,i] <- sapply(x[,i], "[", drop=T)
+ }
+ return(x)
+}
--
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