[R] Extract only the values from a row

Sarah Goslee sarah.goslee at gmail.com
Mon Jul 11 21:57:21 CEST 2011

Hi Sverre,

On Mon, Jul 11, 2011 at 12:48 PM, Sverre Stausland
<johnsen at fas.harvard.edu> wrote:
> Dear helpers,
> how can I extract only the values from a row in a data frame? Using
> [X,] doesn't do the trick:
>> data.frame(letters[1:10],letters[11:20])->my.data
>> my.data[1,]
>  letters.1.10. letters.11.20.
> 1             a              k
> I would like to be able to extract only the values "a" and "k" without
> getting the row names and column names with them. I'm asking because I
> want to assign the character values from a row as the names of the
> columns of the data frame.

You're confusing display with value. R extracts the first row only,
but when it is *printed to the screen* it has all the other parts
shown to help the viewer. They aren't really part of the value

But I bet you tried it before asking, and it didn't work, so you
assumed it was the display values that messed up your attempt. I think
you've actually run into R's default behavior: character columns are
stored as factors unless you specify otherwise.

So try this:
> my.data <- data.frame(letters[1:10],letters[11:20], stringsAsFactors=FALSE)
> my.other.data <- data.frame(1:5, 1:5)
> colnames(my.other.data) <- my.data[1,]
> my.other.data
  a k
1 1 1
2 2 2
3 3 3
4 4 4
5 5 5


Sarah Goslee

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