[R] subsetting based on joint values of critera

[Ista Zahn]

Hi Simon,
You almost had it! Just need to move the negation outside the rest of
the logic, and remove the quotes from year. Not actually tested (no
data), but I think

newdata<- subset(bpa, !(State=="Connecticut" & year<2010))

should do it.

Best,
Ista

On Tue, Jan 25, 2011 at 1:34 PM, Simon Kiss <simonjkiss at yahoo.ca> wrote:
> Dear colleagues, I have a dataset that looks as below.
>
> I would like to make a new dataset that excludes the cases which are joint conjunctions of particular state names and years, so Connecticut and 2010, Maryland and 2010 and Vermont and 2010.
>
> I'm trying the following subset code:
> newdata<- subset(bpa, (!State=="Connecticut" & year<"2010"))
>
> It appears that it's only evaluating both criteria independently and not jointly, so this is returning all cases in 2008 and 2009, leaving out connecticut for those years as well.
> How do I get subset to return a dataset based on the joint occurrence of values of two variables?
>
> Yours,  Simon Kiss
>
> str(bpa)
> 'data.frame':   150 obs. of  5 variables:
>  $ State   : Factor w/ 50 levels "Alabama","Alaska",..: 1 2 3 4 5 6 7 8 9 10 ...
>  $ year    : num  2008 2008 2008 2008 2008 ...
>  $ ban     : num  0 0 0 0 0 0 0 0 0 0 ...
>  $ partisan: Factor w/ 3 levels "democrat","mixed",..: 1 1 1 1 1 1 1 2 3 2 ...
>  $ news    : num  1.67 2 0 0 2.38 ...
> *********************************
> Simon J. Kiss, PhD
> Assistant Professor, Wilfrid Laurier University
> 73 George Street
> Brantford, Ontario, Canada
> N3T 2C9
> Cell: +1 519 761 7606
>
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>



-- 
Ista Zahn
Graduate student
University of Rochester
Department of Clinical and Social Psychology
http://yourpsyche.org