[R] Converting 1-D array to vector

[Ronnen Levinson]

   Hi.
   How  do I convert a one-dimensional array of characters to a character
   vector? In the example below I am trying to get the result c("a","d"). The
   function as.vector() returns the same one-dimensional array, and unlist()
   returns something more complicated than I seek.
   Yours truly,
   Ronnen.
   P.S. E-mailed CCs of posted replies appreciated.
   > df=data.frame(x=letters[1:3],y=letters[4:6])
   > df
     x y
   1 a d
   2 b e
   3 c f
   > df[1,]
     x y
   1 a d
   > as.vector(df[1,])
     x y
   1 a d
   > unlist(df[1,])
   x y
   a d
   Levels: a b c d e f
   > c("a","d") # desired result
   [1] "a" "d"
   > version
                  _
   platform       i386-pc-mingw32
   arch           i386
   os             mingw32
   system         i386, mingw32
   status
   major          2
   minor          7.0
   year           2008
   month          04
   day            22
   svn rev        45424
   language       R
   version.string R version 2.7.0 (2008-04-22)

   --
   Ronnen Levinson, Ph.D.
   scientist, Lawrence Berkeley National Lab
   The  Onion  horoscope: Libra September 23 - October 23 Your tactics of
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