baptiste auguie wrote:
> Dear list,
>
> I often need to convert several variables from numeric or integer into
> factors (before plotting, for instance), as in the following example,
>
>
> d <- data.frame(
> x = seq(1, 10),
> y = seq(1, 10),
> z = rnorm(10),
> a = letters[1:10])
>
>
> d2 <-
> within(d, {
> x = factor(x)
> y = factor(y)
> })
>
> str(d)
> str(d2)
>
>
> I'd like to write a function factorise() which takes a data.frame and
> a vector of variable names, and returns the original data.frame with
> the desired variables converted to factor,
>
would this not be good enough:
# dummy data
data = data.frame(x=1:10, y=1:10)
# a factorizer
factorize = function(data, columns=names(data)) {
data[columns] = lapply(data[columns], as.factor)
data }
sapply(factorize(data, 'x'), is)
# $x "factor" ...
# $y "integer" ...
lapply(factorize(data), is)
# $x "factor" ...
# $y "factor" ...
> factorise <- function(d, f)
> ***ply(d, f, factor) # some apply function
>
> also, perhaps a defactorise() function doing the reverse operation
> with as.numeric.
then, perhaps,
# an izer
ize = function(data, columns=names(data), izer=as.factor) {
data[columns] = lapply(data[columns], izer)
data }
ize(data, 'x', as.logical)
or even
ize = function(izer)
function(data, columns=names(data)) {
data[columns] = lapply(data[columns], izer)
data }
logicalize = ize(as.logical)
characterize = ize(as.character)
lapply(logicalize(data), is)
# $x "logical" ...
# $y "logical" ...
lapply(characterize(data, 'x'), is)
# $x "character" ...
# $y "integer" ...
etc.
vQ
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