[R] How to convert Charagter variables into numeric

[John Fox]

Dear Arup,

It's very difficult to know what's going on without more information. What
is the form of the data that you're importing and how are you reading the
data? I ask because the most common way of getting data into R is probably
via read.table(), which by default converts character data to factors but
reads numbers as numeric. If a "column" of input data has one or more
non-numeric entries (other than the default missing-data indicator NA), it
will be read as a factor, even if most entries in the column are numbers.

To answer your more general question, R has a number of "coercion" functions
prefixed by "as." for changing data from one form to another: For example,
if by "numeric to categorical" you mean numeric to a factor, then
as.factor() will do the trick. There is also the more general coercion
function as() (see ?as).

I hope this helps,
 John

------------------------------
John Fox, Professor
Department of Sociology
McMaster University
Hamilton, Ontario, Canada
web: socserv.mcmaster.ca/jfox


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On
> Behalf Of Arup
> Sent: February-06-09 1:51 AM
> To: r-help at r-project.org
> Subject: [R] How to convert Charagter variables into numeric
> 
> 
> I am importing a dataset in R where some of the variable are numerical and
> some of them are character...but the problem is that R is treating
> numerical variables as character (I am using "is.character" to judge the
> type). Now the question is how can I convert these character variables
into
> numeric and also let me know about the other conversion like "numeric to
> categorical","numeric to continuous" etc.Thank you.
> 
> Arup
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