On Apr 19, 2009, at 6:45 PM, Grze? wrote:
>
> I have database write as .csv file.
The external sorage format is not likely to be relevant. What might be
informative would be to produce the code that reads this
file.>
> When I want to get sth from my database I get NULL, but I know that
> there is
> sth!
> For example:
>
>> data$ID
> NULL
>> data$kod
> NULL
>
> but command like below is always recognize by R
>> data[2,3]
> [1] '082'
Tell is what happens when you enter:
str(data)
class(data)
Perhaps the third column is not named "ID" or "kod" or the
object is
not a data.frame, but is rather a matrix.
--
David Winsemius>
>
> In my opinion this problem is also connect with my attempt to create
> a tree.
> I always get errors.
>
>> t.tree0=rpart(ID~.,t.train)
> Error in eval(expr, envir, enclos) : object "ID" not found
>
>> t.tree0=rpart(kod~.,t.train)
> Error in eval(expr, envir, enclos) : object "kod" not found
>
> What I should do to create my simple trees?
> --
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>
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David Winsemius, MD
Heritage Laboratories
West Hartford, CT