[R] transforming character categories

[Gabor Grothendieck]

Try this.  It matches the first numeric string on
each line applying as.numeric to it and then using
c to simplify the resulting list to a numeric vector.

> x <- c("from 1000$ to 2000$", "from 2000$  to 3000$", "more than 3000$",
+ "from 1000$ to 2000$", "from 1000$ to 2000$")

> library(gsubfn)
> strapply(x, "([0-9]+).*", as.numeric, simplify = c)
[1] 1000 2000 3000 1000 1000

See the gsubfn home page for more:
http://gsubfn.googlecode.com

On Sun, Jun 28, 2009 at 4:25 AM, Gregor Povh<gregorpovh at yahoo.de> wrote:
>
>
> Dear R users,
>
> apologies for this quite simple question.  I've tried serverall approaches,
> however, could not generate the desired result.
>
> I have a large data frame, which has several cathegories encoded as
> character strings, for example.
>
> Name, income, gender, ...
> ...  "from 1000$ to 2000$"  ...
> ...  "from 2000$  to 3000$" ...
> ...  "more than 3000$"        ...
> ...  "from 1000$ to 2000$"  ...
> ...  "from 1000$ to 2000$"  ...
>
>
> How can I transform this column into numeric values for the categories, for
> example in somethins like this:
> ... 1000 ...
> ... 2000 ...
> ... 3000 ...
> ... 1000 ...
> ... 1000 ...
>
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