[R] How to change levels?

[Ista Zahn]

Hi,

see ?droplevels and/or the "stringsAsFactors" section of ?options

Best,
Ista

On Wed, Jan 16, 2013 at 4:56 AM, paladini <paladini at beuth-hochschule.de> wrote:
> Hello!
> I have got a dataframe with 10 columns and 100 rows. The seventh column
> consists of a lot of country names.
> When I use newdata=subset(data, data[, 7]=="United Kingdom"|data[,
> 7]=="Germany") I get just the rows where the country name is UK or Germany.
> But the level information doesn`t change. That means if I use
> levels(newdata[,7]), I get:
>
>  [1] "Austria"                  "Belgium"
>  [3] "Denmark"                  "Finland"
>  [5] "France"                   "Germany"
>  [7] "Spain"                    "Sweden"
>  [9] "Switzerland"              "The Netherlands"
>  [11] "United Kingdom"           "United States of America"
> That leads to problems in the further data processing .
>
> How can I change the level information to the real levels of newdata?
>
> Thanking you in anticipation
>
> Claudia
>
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