R help - Jul 2009 - Assigning rank based on total count

Hi all,

I am using ACS micro data (PUMS) with one of the columns as a 
factor for the place of birth (POBPF).  I would like to create 
a column (POBR) containing a rank 
corresponding to the place of the observation 
in the POBPF rankings.  For example, 
if a person is from Oregon, Oregon is 
the most popular Place of Birth, so each 
person who came from Oregon should have a 1 
in their POBR.  Each row from 
California would have POBR 2, etc.  

This way I can subset on the most populous sending 
places when doing analyses.

For the life of me I can't figure this out.  
I think some combination of "sort()", 
"xtabs()" and "merge()" should work, 
but my brain seems to be fried.

Tx

Here's a way to get to your solution, but it's not very pretty:

testdfr <-
data.frame(POB=c("Oregon","Oregon","Oregon","New
York","California","California"))

nstates <- length(unique(testdfr$POB))
testdfr$ POBR <- c(nstates:1)[table(testdfr$POB)][testdfr$POB]


greetings,
Remko



-------------------------------------------------
Remko Duursma
Post-Doctoral Fellow

Centre for Plants and the Environment
University of Western Sydney
Hawkesbury Campus
Richmond NSW 2753

Dept of Biological Science
Macquarie University
North Ryde NSW 2109
Australia

Mobile: +61 (0)422 096908



On Fri, Jul 24, 2009 at 8:45 AM, ws<webb.sprague at gmail.com>
wrote:
> Hi all,
>
> I am using ACS micro data (PUMS) with one of the columns as a
> factor for the place of birth (POBPF). ?I would like to create
> a column (POBR) containing a rank
> corresponding to the place of the observation
> in the POBPF rankings. ?For example,
> if a person is from Oregon, Oregon is
> the most popular Place of Birth, so each
> person who came from Oregon should have a 1
> in their POBR. ?Each row from
> California would have POBR 2, etc.
>
> This way I can subset on the most populous sending
> places when doing analyses.
>
> For the life of me I can't figure this out.
> I think some combination of "sort()",
> "xtabs()" and "merge()" should work,
> but my brain seems to be fried.
>
> Tx
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

> I am using ACS micro data (PUMS) with one of the columns as a 
> factor for the place of birth (POBPF).  I would like to create 
> a column (POBR) containing a rank 
> corresponding to the place of the observation 
> in the POBPF rankings.  
I wrote a blog entry on my solution:

http://oregondemographics.wordpress.com/2009/07/25/adding-a-ranking-column-to-a-
data-frame-of-observations/