[R] Converting a data frame to matrix

[jim holtman]

Do an 'str' on your data so that we see what it contains.  It may
appear to be numbers, but they might also be factors as a result of
the read.table.

On Thu, Mar 27, 2008 at 7:43 PM, Adrian Johnson
<oriolebaltimore at gmail.com> wrote:
> Hello:
>
> I have a tab delim file with 100 rows and 100 columns.
>
> I have numerical values in this table. What I want is to create an image
> color map with color gradation.
>
> my values range from -5 to 0. max value is 0.
>
> to acheive this, I need to convert my data.frame into matrix.
>
> I tried following :
>
> mydf <- read.table('mytable',sep='\t',header=T)
> mydf1 <- mydf[,2:100]
> colnames(mydf1) <- as.character(mydf[,1])
>
> here comes the trouble:
>
> mymat <- as.matrix(mydf1)
>
> -- numerical values become character values.  -1 becomes "-1"
>
> mymat <- data.matrix(mydf1)
>
> -- whole matrix is filled with 1,2 and 3.
>
> Is there any other way I can do this.
>
> say row names are city schools
> colnames  are student names
>
> appreciate your help.
>
> Thanks
> AJ
>
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>
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-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?