From: Dimitris Rizopoulos <dimitris.rizopoulos_at_med.kuleuven.be>

Date: Fri 29 Jul 2005 - 00:06:42 EST

Dimitris Rizopoulos

Ph.D. Student

Biostatistical Centre

School of Public Health

Catholic University of Leuven

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Jul 29 00:16:42 2005

Date: Fri 29 Jul 2005 - 00:06:42 EST

maybe something like this could be helpful

city.name <- c("munich", "paris", "tokio", "london", "boston")
X <- cbind(c(2, 5, 5), c(4, 1, 3))

####

matrix(city.name[X], ncol = 2)

I hope it helps.

Best,

Dimitris

Dimitris Rizopoulos

Ph.D. Student

Biostatistical Centre

School of Public Health

Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium

Tel: +32/16/336899 Fax: +32/16/337015 Web: http://www.med.kuleuven.be/biostat/ http://www.student.kuleuven.be/~m0390867/dimitris.htm

- Original Message ----- From: <jhainm@fas.harvard.edu> To: <r-help@stat.math.ethz.ch> Sent: Thursday, July 28, 2005 3:52 PM Subject: [R] replace matrix values with names from a dataframe

*> Hi,
**>
*

> I am looking for a way to replace matrix values with names from a

*> dataframe.
**>
**> Let me do this by example: I have a dataframe:
**>
**>>data
**> city.name
**> 1 munich
**> 2 paris
**> 3 tokio
**> 4 london
**> 5 boston
**>
**> each city name corresponds to only one index number (there is only
**> one
**> observation for each city). After doing some matching I end up with
**> a matrix
**> that looks something like this:
**>
**>> X
**> [,1] [,2]
**> [1,] 2 4
**> [2,] 5 1
**> [3,] 5 3
**> [4,] 12 217
**> [5,] 16 13
**>
**> Here the numbers in the matrix are the index numbers from my
**> original dataset,
**> each row is a matched pair (so e.g. the first row tells me that obs.
**> number 2
**> (i.e. Paris) was matched to obs number 4 (i.e. London)).
**>
**> Now I am looking for a quick way to transform the index numbers back
**> to city
**> names, so that at the end I have a matrix that looks something like
**> this:
**>
**>> X.transformed
**> [,1] [,2]
**> [1,] paris london
**> [2,] boston munich
**> [3,] boston tokio
**> [4,] 12 217
**> [5,] 16 13
**>
**> etc. So instead of the index number, the matrix should contain the
**> names that
**> corresponds to it. In my real data, I have many many names and
**> replacing each
**> value by hand would take too long. Any help is highly appreciated.
**>
**> Thank you.
**>
**> Regards,
**> Jens
**>
**> ______________________________________________
**> R-help@stat.math.ethz.ch mailing list
**> https://stat.ethz.ch/mailman/listinfo/r-help
**> PLEASE do read the posting guide!
**> http://www.R-project.org/posting-guide.html
**>
*

R-help@stat.math.ethz.ch mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html Received on Fri Jul 29 00:16:42 2005

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