Make data.matrix() convert character columns to factor then integer.

git-svn-id: https://svn.r-project.org/R/trunk@76937 00db46b3-68df-0310-9c12-caf00c1e9a41
wch · Aug 8, 2019 · d1d3863 · d1d3863
1 parent ad97e0d
commit d1d3863
Show file tree

Hide file tree

Showing 3 changed files with 9 additions and 8 deletions.
diff --git a/doc/NEWS.Rd b/doc/NEWS.Rd
@@ -35,6 +35,9 @@
       the user level functions \code{.traceback()} and \code{traceback()},
       fulfilling the wish of \PR{17580}, reported (incl. patch proposal)
       by Brodie Gaslam.
+
+      \item \code{data.matrix()} now converts character columns to
+      factors and from this to integers.
     }
   }
 

diff --git a/src/library/base/R/data.matrix.R b/src/library/base/R/data.matrix.R
@@ -1,7 +1,7 @@
 #  File src/library/base/R/data.matrix.R
 #  Part of the R package, https://www.R-project.org
 #
-#  Copyright (C) 1995-2012 The R Core Team
+#  Copyright (C) 1995-2019 The R Core Team
 #
 #  This program is free software; you can redistribute it and/or modify
 #  it under the terms of the GNU General Public License as published by
@@ -26,9 +26,6 @@ data.matrix <- function(frame, rownames.force = NA)
           else if(.row_names_info(frame) <= 0L) NULL
           else row.names(frame)
 
-    stringsAsFactors_default_is_FALSE <-
-        isFALSE(as.logical(Sys.getenv("_R_OPTIONS_STRINGS_AS_FACTORS_")))
-
     for(i in seq_len(d[2L])) {
         xi <- frame[[i]]
         ## at present is.numeric suffices, but let's be cautious
@@ -37,7 +34,7 @@ data.matrix <- function(frame, rownames.force = NA)
             frame[[i]] <- as.integer(xi)
             next
         }
-        if(stringsAsFactors_default_is_FALSE && is.character(xi)) {
+        if(is.character(xi)) {
             frame[[i]] <- as.integer(factor(xi))
             next
         }

diff --git a/src/library/base/man/data.matrix.Rd b/src/library/base/man/data.matrix.Rd
@@ -1,6 +1,6 @@
 % File src/library/base/man/data.matrix.Rd
 % Part of the R package, https://www.R-project.org
-% Copyright 1995-2008 R Core Team
+% Copyright 1995-2019 R Core Team
 % Distributed under GPL 2 or later
 
 \name{data.matrix}
@@ -17,15 +17,16 @@ data.matrix(frame, rownames.force = NA)
 }
 \arguments{
   \item{frame}{a data frame whose components are logical vectors,
-    factors or numeric vectors.}
+    factors or numeric or character vectors.}
   \item{rownames.force}{logical indicating if the resulting matrix
     should have character (rather than \code{NULL})
     \code{\link{rownames}}.  The default, \code{NA}, uses \code{NULL}
     rownames if the data frame has \sQuote{automatic} row.names or for a
     zero-row data frame.}
 }
 \details{
-  Logical and factor columns are converted to integers.  Any other
+  Logical and factor columns are converted to integers.  Character
+  columns are first converted to factors and then to integers. Any other
   column which is not numeric (according to \code{\link{is.numeric}}) is
   converted by \code{\link{as.numeric}} or, for S4 objects,
   \code{\link{as}(, "numeric")}.  If all columns are integer (after