Thank you Henrik and Rolf. My migraine just disappeared. : )
myobjects = ls(pattern='^RH')
dataobj = mget(myTemp,.GlobalEnv)
map = Reduce(merge,dataobj)
did the trick. do.call() didn't cut it for some reason . . . it
returned an " 'x' is missing " error. But Reduce works quite nicely for
the rasters I'm working with.
Thanks again,
Ben
On 6/10/2011 2:06 AM, Henrik Bengtsson wrote:
...and ?mget for retrieving multiple objects as a list. /Henrik
On Thu, Jun 9, 2011 at 10:32 PM, Henrik Bengtsson<h...@biostat.ucsf.edu> wrote:
See ?get and ?do.call. That should be enough.
?Reduce may be an alternative for do.call(), but could also be less
memory efficient.
My $.02
/Henrik
On Thu, Jun 9, 2011 at 7:57 PM, Ben Zaitchik<zaitc...@jhu.edu> wrote:
Hello,
I have a large number of raster objects in memory, with names RH100, RH101,
RH102, etc. (myobjects<- ls(pattern='^RH')).
These rasters are sections of a continuous map, and I would like to combine
them using the RasterObject merge tool in package 'raster.'
Merge expects an input list of raster objects (outmap<-merge(x, y, ...),
where x, y, and ... are raster objects). I can run the command successfully
if I type in every raster object that I want to merge, but this is
impractical for the large number of objects I'm combining.
I would like to apply merge to a list of object names defined using some
kind of wildcard-based list command, but I'm struggling to find the right
data types in R.
Is there some way to convert a vector of strings (e.g.,
as.vector(ls(pattern='^RH'))) to a vector of object names (as.names??) that
could be specified as the input to the merge function? What I'd really like
to do is something like outmap<-merge(myobjects[1:40]), in order to merge
the 40 raster objects, but I recognize that it might not be so simple.
Advance apologies if this is already dealt with on the help list . . . I've
gone in circles on wildcard, lapply, and names threads and haven't managed
to get anything to work.
Thank you,
Ben
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