On Thu, 12 Jun 2008, Birgitle wrote:
I have an additional question concerning to this topic.
I usually use something liek that:
read.table(****, colClasses=c("numeric", "factor", "character",
"my.funny.class"))
but why can I not implement "ordered.factor" in there?
Because the help page says
colClasses: character. A vector of classes to be assumed for the
columns. Recycled as necessary, or if the character vector
is named, unspecified values are taken to be 'NA'.
Possible values are 'NA' (when 'type.convert' is used),
'"NULL"' (when the column is skipped), one of the atomic
vector classes (logical, integer, numeric, complex,
character, raw), or '"factor"', '"Date"' or '"POSIXct"'.
Otherwise there needs to be an 'as' method (from package
'methods') for conversion from '"character"' to the specified
formal class.
There is no as.ordered.factor() nor as() method, and nothing in the data
can specify the order of the levels unambiguously. So unless one accepts
a guess (and in R we try not to do that for you, as in e.g. as.Date with
numbers), there is no possibility to support ordered factors.
Birgit
Kenn Konstabel wrote:
Conversion to factor may happen (and often does) when you read in data
with
read.table(). So one solution may be reading in the same data again in a
slightly different way:
read.table(file="mydatafile", as.is=TRUE)
# see also ?read.table
You can also specify a class to each column of the data you're about to
read
in:
read.table(****, colClasses=c("numeric", "factor", "character",
"my.funny.class"))
Ad take a look at http://cran.r-project.org/doc/FAQ/R-FAQ.html p.
7.10
for the right answer -- in any case, don't use as.numeric(x)!
Kenn
On Thu, Jun 12, 2008 at 9:24 AM, Qman Fin <[EMAIL PROTECTED]> wrote:
Hi all,
I have some data x, which are actualy consisted of numerical enties. But
the
class of this matrix is set to be "factor" by someone else. I used
"class(x)", it turns out to be "factor". So I can not calculate them.
How can I turn them into numerical data so that I can apply math
operations
on them? Thanks a lot for your help.
Selina
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--
Brian D. Ripley, [EMAIL PROTECTED]
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
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