# Re: [R] Descriptive statistics for tables

From: Jean Eid <jeaneid_at_chass.utoronto.ca>
Date: Sat 01 Oct 2005 - 01:18:09 EST

I do not totally understand your question as well. You seem to want a descriptive statistic about a unitary number. What is the sd of a number? or any other descriptive statictic. Maybe you mean for the columns or rows or it could be that these are t-stats or z-stats that you need to get p_values for them. In any case what I would do assuming that these tables are in your env is the following

sapply(ls(), function(x){
nam <- paste(x,"_summary", sep="")
tt <- colMeans(get(x))
assign(nam, tt, pos=1)})

The function above will output a number of tables with their original name an extension _summary which contains the column means of the tables.

If you have the tables in different files on your box you need to add a read.table line above. and the function becomes

sapply(dir(), function(x){

nam <- paste(x,"_summary", sep="")

tt <- colMeans(x)
assign(nam, tt, pos=1)})

HTH On Fri, 30 Sep 2005, DAVID CAMACHO wrote:

>
> What I need is extremely simple. And I suppose there
> are so many way to do it.
> But as I have so many files to do it, I am looking for
> the simplest way (if possible)
>
> What I meant was that I have tables with the same
> numbers of rows and columns, (square form, should I
> say?) like:
>
> 2,5,7
> 3,4,8
> 2,9,3
>
> 5,3,8
> 2,5,5
> 5,7,8
>
> But I have hundreds of this onces, (bigger once).
> Every one of this tables have the same size (columns,
> rows). And I want to obtain the sd, z-score, and
> p-value for the position [1,1], [1,2]....
> [2,1],[2,2]... etc etc. That is, to obtain a table
> with some simple descriptive statistics about all this
> tables.
> I have try different methods, but I am no familiar
> with R. (by the way, I could not find the way to do
> loops with R)
> Any suggestion is welcome.
> David
>
>
>
>
>
> --- Berton Gunter <gunter.berton@gene.com> wrote:
>
> > I don't know what a "quadratic, same size" table is
> > or what you mean. If you
> > do not get a satisfactory reply I suggest:
> >
> > 1. Read and follow the posting guide at the end of
> > this message.
> >
> > 2. In particular, provide a simple, reproducible
> > example to show what you
> > want to do and perhaps any error messages that you
> >
> >
> > -- Bert Gunter
> > Genentech Non-Clinical Statistics
> > South San Francisco, CA
> >
> >
> > > -----Original Message-----
> > > From: r-help-bounces@stat.math.ethz.ch
> > > [mailto:r-help-bounces@stat.math.ethz.ch] On
> > Behalf Of DAVID CAMACHO
> > > Sent: Thursday, September 22, 2005 9:10 AM
> > > To: r-help@stat.math.ethz.ch
> > > Subject: [R] Descriptive statistics for tables
> > >
> > >
> > > I have a lot (more than one hundred) of files with
> > tables of
> > > the same kind (quadratic, same size) and I want to
> > obtain
> > > some statistics for every position on them.
> > Therefore, as a
> > > result I want another table. I import every table,
> > and create
> > > an object read.table for it, then I have try to
> > create a
> > > list or a data frame and directly utilize some
> > functions
> > > like sd( ) without success, because it calculate
> > sd for the
> > > columns . Which kind of object should I create
> > in order to
> > > utilize directly this kind of functions? Should I
> > program it
> > > throw for loops?
> > >
> > > David
> > >
> >
>
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