[R] parse on left hand side of R assignment
Prof Brian Ripley
ripley at stats.ox.ac.uk
Sat May 31 19:55:36 CEST 2003
On Sat, 31 May 2003, Paul E. Johnson wrote:
> I keep finding myself in a situation where I want to calculate a
> variable name and then use it on the left hand side of an assignment.
> For example
> iteration <- 1
> varName <- paste("run",iteration,sep="")
> myList$parse(text=varName) <- aColumn
> I want to take some existing variable "aColumn" and use the name
> "varName" name for it and put it into a list "myList". That use fails
> with this error:
> Error: couldn't find function "(<-"
> I've tried many variations on the theme.
> If I could do this with a data frame, I would be just as happy. Right
> now I'm using a list rather than a data frame because not all columns
> are of the same length. But I can work around that.
For a data frame you could use
mydf[paste("run",iteration,sep="")] <- aColumn
and for a list or a data frame
Robject[[paste("run",iteration,sep="")]] <- aColumn
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 272866 (PA)
Oxford OX1 3TG, UK Fax: +44 1865 272595
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