Re: [R] name ONLY one column // empty.dimnames() in 'sfsmisc'
IC == Ivan Calandra ivan.calan...@uni-hamburg.de
on Mon, 27 Sep 2010 16:59:31 +0200 writes:
IC Hi,
IC I'm not sure it's even possible (and if it is I don't know how, but I'm
IC no expert).
yes it is possible (in some way), see below.
IC But I think it doesn't make much sense to have only one named column.
IC Just give it a vector:
IC vect_names - c(myname1, myname2, myname3)
IC colnames(my_matrix) - vect_names
yes, exactly, ... but read on
IC HTH,
IC Ivan
IC Le 9/27/2010 10:26, Lorenzo Cattarino a écrit :
Hi R-users
I can not change the name of one column only of my matrix.
my_matrix - matrix (1:12,ncol=3)
colnames(my_matrix)[1] - 'myname'
Error in dimnames(x)- dn :
length of 'dimnames' [2] not equal to array extent
Just read ... and maybe re-read this error message. It is
exactly on target:
The colnames are the dimnames(.)[2] and they have the wrong length.
{ I'm too often disappointed that many R users read only the
first, or actually the zero-th word of the 'very fine' error
messages that we provide you with (most of the time):
Such useRs only read up to Error .. and are put off, saying
It does not work or Why can't I ... or
}
Now back to the original question:
What you want is to give empty column names to all but the
first column.
mat - matrix(1:12, 3)
colnames(mat) - c(myname, , )
And a note: giving empty column- and row-names is sometimes
desirable if just for printing.
For that reason, our 'sfsmisc' CRAN package has contained the function
empty.dimnames() for many years now (actually longer than R
exists; we had it as an S+ function in our goodies
collection). Excerpt from its help page:
empty.dimnames package:sfsmisc R Documentation
Empty Dimnames of an Array.
Description:
`Remove' all dimension names from an array for compact printing.
Usage:
empty.dimnames(a)
Arguments:
a: an ‘array’, especially a matrix.
Value:
Returns ‘a’ with its dimnames replaced by empty character strings.
Author(s):
Bill Venables / Martin Maechler, Sept 1993.
and here the examples we provide:
example(empty.dimnames)
empty. empty.dimnames(diag(5)) # looks much nicer
1 0 0 0 0
0 1 0 0 0
0 0 1 0 0
0 0 0 1 0
0 0 0 0 1
empty. (a - matrix(-9:10, 4,5))
[,1] [,2] [,3] [,4] [,5]
[1,] -9 -5 -137
[2,] -8 -4048
[3,] -7 -3159
[4,] -6 -226 10
empty. empty.dimnames(a) # nicer, right?
-9 -5 -1 3 7
-8 -4 0 4 8
-7 -3 1 5 9
-6 -2 2 6 10
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[R] name ONLY one column
Hi R-users I can not change the name of one column only of my matrix. my_matrix - matrix (1:12,ncol=3) colnames(my_matrix)[1] - 'myname' Error in dimnames(x) - dn : length of 'dimnames' [2] not equal to array extent thank you for your help Lorenzo [[alternative HTML version deleted]] __ R-help@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.
Re: [R] name ONLY one column
Hi Lorenzo, The problem is that my_matrix does not have dimnames. See below. my_matrix - matrix (1:12,ncol=3) str(my_matrix) ## does not have dimnames dimnames(my_matrix) ## dimnames is NULL colnames(my_matrix) - myname # fails because you are trying to alter the value of something that does not exist ## solution: Set colnames colnames(my_matrix) - 1:dim(my_matrix)[2] str(my_matrix) # my_matrix now has colnames colnames(my_matrix)[1] - myname # and now we can alter them On Mon, Sep 27, 2010 at 8:26 AM, Lorenzo Cattarino l.cattar...@uq.edu.au wrote: Hi R-users I can not change the name of one column only of my matrix. my_matrix - matrix (1:12,ncol=3) colnames(my_matrix)[1] - 'myname' Error in dimnames(x) - dn : length of 'dimnames' [2] not equal to array extent thank you for your help Lorenzo [[alternative HTML version deleted]] __ R-help@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. -- Ista Zahn Graduate student University of Rochester Department of Clinical and Social Psychology http://yourpsyche.org __ R-help@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.
Re: [R] name ONLY one column
Hi, It is because the column names do not exist. If you cast the matrix as a data frame your code would work. jon -Original Message- From: r-help-boun...@r-project.org [mailto:r-help-boun...@r-project.org] On Behalf Of Lorenzo Cattarino Sent: 27. september 2010 10:27 To: r-help@r-project.org Subject: [R] name ONLY one column Hi R-users I can not change the name of one column only of my matrix. my_matrix - matrix (1:12,ncol=3) colnames(my_matrix)[1] - 'myname' Error in dimnames(x) - dn : length of 'dimnames' [2] not equal to array extent thank you for your help Lorenzo [[alternative HTML version deleted]] __ R-help@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. __ R-help@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.
Re: [R] name ONLY one column
Hi, I'm not sure it's even possible (and if it is I don't know how, but I'm no expert). But I think it doesn't make much sense to have only one named column. Just give it a vector: vect_names - c(myname1, myname2, myname3) colnames(my_matrix) - vect_names HTH, Ivan Le 9/27/2010 10:26, Lorenzo Cattarino a écrit : Hi R-users I can not change the name of one column only of my matrix. my_matrix- matrix (1:12,ncol=3) colnames(my_matrix)[1]- 'myname' Error in dimnames(x)- dn : length of 'dimnames' [2] not equal to array extent thank you for your help Lorenzo [[alternative HTML version deleted]] __ R-help@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. -- Ivan CALANDRA PhD Student University of Hamburg Biozentrum Grindel und Zoologisches Museum Abt. Säugetiere Martin-Luther-King-Platz 3 D-20146 Hamburg, GERMANY +49(0)40 42838 6231 ivan.calan...@uni-hamburg.de ** http://www.for771.uni-bonn.de http://webapp5.rrz.uni-hamburg.de/mammals/eng/mitarbeiter.php [[alternative HTML version deleted]] __ R-help@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.
