[R] Creating subsets of a matrix

[Joshua Wiley]

Hi,

Try looking at ?subset

I think something like this should work:

dat.male <- subset(dat, gender == "male")
dat.female <- subset(dat, gender == "female")

though it may require tweaking depending how your data is stored.  If
you want more specific help, suppose your matrix is called "dat" (but
substitute the actual name of it in), send us (or me) the output from:

dput(dat)
or if that is incredibly long, just
str(dat)

Here is a little example with a builtin dataset using subset():

print(mtcars) # show the data

## save and show all rows where column 'vs' is equal to 1
(dat.1 <- subset(mtcars, vs == 1))
## save and show all rows where column 'vs' is equal to 0
(dat.0 <- subset(mtcars, vs == 0))

Hope this helps,

Josh

On Sun, Jan 23, 2011 at 10:36 AM, poolmunch <poolmunch at gmail.com> wrote:
>
> Hello,
>
> Say I have 2 columns, bmi and gender, the first being all the values and the
> second being male or female. How would I subset this into males only and
> females only? I have searched these fora and read endlessly about select[]
> and split() functions but to no avail. Also the table is not ordered.
>
>     bmi gender        ->      bmi gender         +    bmi  gender
> 1  24.78   male              1 24.78   male           3 23.18  female
> 2  26.42   male              2 26.42   male           4 22.36  female
> 3  23.18 female              ...                          ...
> 4  22.36 female
> ...
>
> Thank you in advance
> --
> View this message in context: http://r.789695.n4.nabble.com/Creating-subsets-of-a-matrix-tp3232838p3232838.html
> Sent from the R help mailing list archive at Nabble.com.
>
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>



-- 
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/