R help - Jun 2009 - transforming character categories

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 ...

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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>