[R] convert factor dataframe into numeric matrix

[sun]

I took a look at these two ref cards and indeed they are helpful, but still 
they are not complete enough to include this data.matrix() function in 
particular.


----- Original Message ----- 
From: "John Kane" <jrkrideau at yahoo.ca>
To: "sun" <flyhyena at yahoo.com.cn>; <r-help at stat.math.ethz.ch>
Sent: Wednesday, October 24, 2007 4:36 PM
Subject: Re: [R] convert factor dataframe into numeric matrix


> You might want to have a look at the two "R reference
> card" documents under "Contributed" on CRAN.
>
> --- sun <flyhyena at yahoo.com.cn> wrote:
>
>>
>> ----- Original Message ----- 
>> From: "Prof Brian Ripley" <ripley at stats.ox.ac.uk>
>> To: "sun" <flyhyena at yahoo.com.cn>
>> Cc: <r-help at stat.math.ethz.ch>
>> Sent: Wednesday, October 24, 2007 2:58 PM
>> Subject: Re: [R] convert factor dataframe into
>> numeric matrix
>>
>>
>> > On Wed, 24 Oct 2007, sun wrote:
>> >
>> >> Bear me if this is a naive question.
>> >>
>> >> I have a dataframe, all lists inside it are
>> factors. When I use
>> >
>> > Do you mean 'all columns are factors'?  A data
>> frame is a list but usually
>> > does not contain lists.
>> >
>> >> as.matrix(df) to convert, I get a character
>> matrix while my intention is
>> >> to
>> >> get numeric matrix. I can make the convertion
>> iteratively by each list
>> >> but
>> >> I do think there is some more elegant way of
>> doing this.
>> >>
>> >> please let me know if I missed somthing there.
>> >
>> > ?data.matrix  may be what you are looking for: you
>> gave us too little
>> > detail to be sure.
>> >
>>
>>
>> Thanks for your helps. I did not provide data 'cause
>> I thought this is FAQ
>> type of question(maybe wrong impression).
>> Actually I use algdesign generated a factorial
>> design data frame in which:
>> >
>> > str(dat)
>> 'data.frame':   2304 obs. of  6 variables:
>>  $ party : Factor w/ 3 levels "1","2","3": 1 2 3 1 2
>> 3 1 2 3 1 ...
>>  $ dinner: Factor w/ 3 levels "1","2","3": 1 1 1 2 2
>> 2 3 3 3 1 ...
>>  $ d1    : Factor w/ 4 levels "1","2","3","4": 1 1 1
>> 1 1 1 1 1 1 2 ...
>>  $ p1    : Factor w/ 4 levels "1","2","3","4": 1 1 1
>> 1 1 1 1 1 1 1 ...
>>  $ d2    : Factor w/ 4 levels "1","2","3","4": 1 1 1
>> 1 1 1 1 1 1 1 ...
>>  $ p2    : Factor w/ 4 levels "1","2","3","4": 1 1 1
>> 1 1 1 1 1 1 1 ...
>>
>> I just figured out a way fo convert it to numeric
>> matrix using
>> >d = as.data.frame(lapply(dat,as.numeric))
>>
>> but "data.matrix()" suggested by Prof. Brian and Mr.
>> Dimitris is exactly the
>> thing I was looking for.
>>
>> I am not sure if there exist some documents or
>> online source that have
>> documented these kind of "utility functions"
>> categorized in somet categories
>> like "data types", "data manipulating functions",
>> "variable scopes", etc.,
>> that allow a quick browsing for some functions or
>> other information.
>>
>> Thanks for your kind helps.
>>
>> Kind regards,
>> Sun
>>
>> ______________________________________________
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>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained,
>> reproducible code.
>>
>
>
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