From: Michael Bach <phaebz_at_gmail.com>

Date: Tue, 19 Apr 2011 15:21:13 +0300

R-help_at_r-project.org mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Tue 19 Apr 2011 - 12:24:20 GMT

Date: Tue, 19 Apr 2011 15:21:13 +0300

Petr PIKAL <petr.pikal_at_precheza.cz> writes:

*> Hi
**>
*

> r-help-bounces@r-project.org napsal dne 19.04.2011 09:46:47:

*>
**>> Dear R Users,
**>>
**>> Lets assume I have this data frame:
**>>
**>> x y z
**>> 1 1.00 5 0.5
**>> 2 1.02 5 0.7
**>> 3 1.04 7 0.1
**>> 4 1.06 9 0.4
**>>
**>> x and y columns are sorted and the values not necessarily integers. z
**>> values are not sorted. Now I would like to create a matrix out of this
**>> with x as first column values and y as first row values. Matrix element
**>> a_11 shall be left NA. The a_ij should have the z value for the
**>> corresponding x and y pair. The result shall be some sort of a grid and
**>> then e.g. look like:
**>>
**>> [,1] [,2] [,3] [,4] [,5]
**>> [1,] NA 5 6 7 9 (y)
**>> [2,] 1.00 0.5 NA NA NA
**>> [3,] 1.02 0.7 NA NA NA
**>> [4,] 1.04 NA NA 0.1 NA
**>> [5,] 1.06 NA NA NA 0.4
**>> (x)
**>>
**>> This example is just for illustration. The resulting matrix should have
**>> more numeric values than NA's.
**>
**> I am not sure if this is the solution you want
**>
**> tab<-xtabs(z~x+y, data=df)
**> tab[tab==0]<-NA
**>
*

This looks right, but the resulting table does not have rows == columns and there are also no missing values (0 or NA) which should be there. I think I did not make myself clear, please see also my reply to the previous answer to my question by David Winsemius.

Thanks for your reply though!

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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Tue 19 Apr 2011 - 12:24:20 GMT

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