R help - Oct 2010 - is get() really what I want here?

# Let's say I have 5 objects, object_1, object_2, etc.
for (i in 1:5) {
    assign(paste("object_",i, sep=""), i+500)
}

# Now, for whatever reason, I don't know the names of the objects I've
created, but I want to operate on them.
list<-ls(pattern="^obj")

#Is get best?
for (l in list) {
    cat("\n", l, "is", get(l), sep=" ")
}

Is get() the correct command to use in this situation?  What if rather than
just an integer, object_1 etc are large arrays - does that change the
answer, for speed reasons?

Thanks in advance,
Dan

	[[alternative HTML version deleted]]

Hi Daniel,

get() will work for any object, but cat() may not.  cat() should work
for arrays, but it will be messy even for relatively small ones.  For
example, run:
cat("Hello", array(1:100, dim = c(10, 10)), sep = " ")

What are you really trying to do?  If you are just trying to figure
out what random variables in your workspace you've assigned but do not
know/forgot what they are, consider:

ls.str(pattern="^obj")

as a better way to get their names and some useful summaries
(including class and number of observations).

HTH,

Josh

On Tue, Oct 19, 2010 at 10:29 PM, Daniel Weitzenfeld
<dweitzenfeld at gmail.com> wrote:
> # Let's say I have 5 objects, object_1, object_2, etc.
> for (i in 1:5) {
> ? ?assign(paste("object_",i, sep=""), i+500)
> }
>
> # Now, for whatever reason, I don't know the names of the objects
I've
> created, but I want to operate on them.
> list<-ls(pattern="^obj")
>
> #Is get best?
> for (l in list) {
> ? ?cat("\n", l, "is", get(l), sep=" ")
> }
>
> Is get() the correct command to use in this situation? ?What if rather than
> just an integer, object_1 etc are large arrays - does that change the
> answer, for speed reasons?
>
> Thanks in advance,
> Dan
>
> ? ? ? ?[[alternative HTML version deleted]]
>
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>


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