[R] Calculating proportions from a data frame rather than a table

[John Kane]

--- Farrel Buchinsky <fjbuch at gmail.com> wrote:

> How do you create a table from a data frame? I tried
> as.table(
> name.of.data.frame) but it bombed out.
> I will include the exact error message in my next
> posting. If I recall
> correctly, it said that the data.frame could not be
> coerced to a table.

I may have misunderstood you. I was just thinking that
you could get individual tables of interest from
data.frame dff by
table(dff[,1],dff[,2]) and so on.  


> 
> 
> On 10/2/07, John Kane <jrkrideau at yahoo.ca> wrote:
> >
> > What am I missing here?
> >
> > Cannot you just create the table from the
> data.frame
> > and apply prop.table()to it?
> >
> > --- Farrel Buchinsky <fjbuch at gmail.com> wrote:
> >
> > > When one has raw data it is easy to create a
> table
> > > of one variable against
> > > another and then calculate proportions
> > > For example
> > > a.nice.table<-table(a,b)
> > > prop.table(a.nice.table,1)
> > >
> > > However, I looked at several papers and created
> a
> > > data frame of the
> > > aggregate data. That means I acually created a
> table
> > > except it is a data
> > > frame. The first column lists the name of the
> first
> > > author and the year.
> > > I cannot find how to convert the data frame to a
> > > table so I can use great
> > > functions such as prop.table and margin.table.
> > >
> > > Alas I tried, rowSums but it provides lousy
> output
> > > without listing the names
> > > of th papers.
> > > I have thought of going through the reshape
> package
> > > but I suspect that there
> > > is an easier way to convert a data frame to a
> table.
> > > Is there?
> > >
> > > --
> > > Farrel Buchinsky
> >
> >
> >
> >      Be smarter than spam. See how smart SpamGuard
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> >
> >
> 
> 
> -- 
> Farrel Buchinsky
> GrandCentral Tel: (412) 567-7870
>