Re: [R] reading a matrix from a file

From: Francisco J. Zagmutt <gerifalte28_at_hotmail.com>
Date: Wed 28 Jun 2006 - 02:32:36 EST


Dear Cuau

More details on your posting would have helped. From your example it seems that the matrix you are trying to import is just a comma Separated text file. If that's the case, you can use read.csv and matrix to import those numbers and then make a matrix in R. Assuming the matrix has 3 rows and 4 columns you can do the following:

x=read.csv("mymatrix.txt", header=FALSE) #Reads your file dim(x) #Tells you the dimensions of object x in rows and columns [1] 3 4

newMat= as.matrix(x) #Creates matrix from imported data is.matrix(newMat) #Tests whether the object newMat is of class matrix [1] TRUE I hope this helps

Francisco

Dr. Francisco J. Zagmutt
College of Veterinary Medicine and Biomedical Sciences Colorado State University

>From: Cuau <cuauv@yahoo.com>
>To: r-help@stat.math.ethz.ch
>Subject: [R] reading a matrix from a file
>Date: Tue, 27 Jun 2006 08:06:36 -0700 (PDT)
>
>
> Hello everyone,
>
> I'm writting a little script that will read a matrix from a file
>
> i.e.
>
> 0,.11,.22,.4
> .11,0,.5,.3
> .22,.5,0,.7
> anb so on
>
> and will then calculate some standard stats for nets (i.e.
>centralization, degree, etc).
>
> So far I have opened the file and read the contents, however I' m
>using readLines(filename)
> to read the file and it returns it as one big String with no divitions.
>I tried using
> strsplit(String)
> to split it but eventhough is working I'm not able to put the output of
>the above into a matrix.
>
> Below is an example of what I have done
>
>
> > INfile<-file("mTest.txt", "r")
> > readLines(INfile)->matrix
> > matrix
> [1] "1, 2, 3"
> > strsplit(matrix, ",")->splitLine
> > splitLine
> [[1]]
> [1] "1" " 2" " 3"
>
> > netMatrix <-matrix(c(splitLine), nrow=1,ncol=3)
> > netMatrix
> [,1] [,2] [,3]
> [1,] Character,3 Character,3 Character,3
>
>
> Does anyone have an idea how can I read a matrix and store it in the
>form of a matrix.
>
> thks
>
> -Cuau Vital
>
>
>
>---------------------------------
>
> [[alternative HTML version deleted]]
>
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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 Wed Jun 28 02:47:28 2006

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