[R] specifying dataframe column names in loops
Prof Brian Ripley
ripley at stats.ox.ac.uk
Fri Jul 4 20:50:32 CEST 2003
Sounds like you need to use substitute(). Something like
eval(substitute(lf <- locfit(~s, data=age), list(s=s)))
Formulae are different: I don't see why density() should be.
On Fri, 4 Jul 2003, Simon Goodman wrote:
> Dear list members,
> This is probably a naive question (from a new user), but I'm having problems
> getting column
> names to be recognised in loop that is supposed to apply a set of
> calculations in turn
> to each column of a dataframe.
> The dataframe has 33 columns of output from a simulation.
> The columns each have a text name and I want to apply the same set of
> to each column in turn. These include some self-defined functions that refer
> back to the
> column in the current iteration.
> Setting up a 'for' loop and using age[s] (where 'age' is the dataframe and
> 's' is the iterator) to specify
> each column works for things like 'max' and 'min'. However for functions
> like 'density' or locfit,
> error messages are generated:
> Error in model.frame(formula, rownames, variables, varnames, extras,
> extranames, :
> invalid variable type
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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