[R] Transforming a string to a variable's name? help me newbie...
dwinsemius at comcast.net
Mon Dec 8 16:39:08 CET 2008
On Dec 8, 2008, at 10:11 AM, tsunhin wong wrote:
> Dear all,
> I'm a newbie in R.
> I have a 45x2x2x8 design.
> A dataframe stores the metadata of trials. And each trial has its own
> data file: I used "read.table" to import every trial into R as a
> dataframe (variable).
> Now I dynamically ask R to retrieve trials that fit certain selection
> criteria, so I use "subset", e.g.
> tmptrialinfo <- subset(trialinfo, (Subject==24 & Filename=="v2msa8"))
> The name of the dataframe / variable of an individual trial can be
> obtained using:
> Then I get a string:
> which is of the exact same name of the dataframe / variable of that
> trial, which is:
> Can somebody tell me how can I change that string (obtained from
> "paste()" above) to be a usable / manipulable variable name, so that I
> can do something, such as:
> tmptrial <- trialcompute(trialextract(
> instead of hardcoding:
> tmptrial <-
It may have something to do with the semantics of trialextract about
which most useRs will know nothing (and I was unsuccessful in finding
a function by that name with an Rsitesearch). It seems strange that a
function would accept an unquoted reference to what is obviously a
file name. Perhaps you should be offering that code for inspection
rather than asking how to make a simple assignment. It is possible
that what you are really asking is answered by Faq 7.21:
> Currently, 1) doesn't work...
Saying "doesn't work" is not specific enough. What exactly was the
> Thanks in advance for your help!
> R-help at r-project.org mailing list
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
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