Calculating proportions from a data frame rather than a table

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.

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

is at giving junk email

http://mrd.mail.yahoo.com/try_beta?.intl=ca

-- 
Farrel Buchinsky
GrandCentral Tel: (412) 567-7870