From landronimirc at gmail.com  Tue Aug  2 13:55:01 2011
From: landronimirc at gmail.com (Liviu Andronic)
Date: Tue, 2 Aug 2011 13:55:01 +0200
Subject: [Rd] 'data.frame' method for base::rep()
Message-ID: <CABxs9VmouqjKpNvkzG5emHevXQtTRo9f81nxhOS9FvBo5V4maw@mail.gmail.com>

Dear R developers
Would you consider adding a 'data.frame' method for the base::rep
function? The need to replicate a df row-wise can easily arise while
programming, and rep() is unable to handle such a case. See below.
> x <- iris[1, ]
> x
  Sepal.Length Sepal.Width Petal.Length Petal.Width Species
1          5.1         3.5          1.4         0.2  setosa
> rep(x, 2)
$Sepal.Length
[1] 5.1

$Sepal.Width
[1] 3.5

$Petal.Length
[1] 1.4

$Petal.Width
[1] 0.2

$Species
[1] setosa
Levels: setosa versicolor virginica

$Sepal.Length
[1] 5.1

$Sepal.Width
[1] 3.5

$Petal.Length
[1] 1.4

$Petal.Width
[1] 0.2

$Species
[1] setosa
Levels: setosa versicolor virginica


I found a 'rep.data.frame' function in package 'mefa' [2], but I think
it would be nice to have it in base R. In any case, the code used by
the method is very simple.
> require(mefa)
Loading required package: mefa
mefa 3.2-1 	 2011-05-13
> mefa:::rep.data.frame
function (x, ...)
as.data.frame(lapply(x, rep, ...))
<environment: namespace:mefa>

And here's the example above:
> rep(x, 2)
  Sepal.Length Sepal.Width Petal.Length Petal.Width Species
1          5.1         3.5          1.4         0.2  setosa
2          5.1         3.5          1.4         0.2  setosa


Please le t me know what you think. Regards
Liviu

[1] http://finzi.psych.upenn.edu/R/library/mefa/html/rep.data.frame.html
[2] http://cran.at.r-project.org/web/packages/mefa/index.html


-- 
Do you know how to read?
http://www.alienetworks.com/srtest.cfm
http://goodies.xfce.org/projects/applications/xfce4-dict#speed-reader
Do you know how to write?
http://garbl.home.comcast.net/~garbl/stylemanual/e.htm#e-mail



[Rd] 'data.frame' method for base::rep()
Liviu Andronic