[R] data$ID -> I always get a NULL

[Grześ]

This is my result:

> class(data)
[1] "data.frame"

> str(data)
'data.frame':	2193 obs. of  83 variables:
 $ X.ID.                               : Factor w/ 2193 levels "'18201'",..:
1 2 3 4 5 6 7 8 9 10 ...
 $ X.kod.                       : Factor w/ 20 levels "'01'","'02'",..: 1 1
1 1 1 1 1 1 1 1 ...
 $ X.wiel.                         : int  7 7 7 7 7 7 7 8 8 8 ...
 $ X.piech.                     : num  1 99.9 4 0.5 4 2 99.9 2 2 99.9 ...
 $ X.rodz.                       : int  NA 2 4 NA 4 2 2 3 2 NA ...



David Winsemius wrote:
> 
> 
> On Apr 19, 2009, at 6:45 PM, Grześ 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?
>> -- 
>> View this message in context:
>> http://www.nabble.com/data%24ID--%3E-I-always-get-a-NULL-tp23128214p23128214.html
>> Sent from the R help mailing list archive at Nabble.com.
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://stat.ethz.ch/mailman/listinfo/r-help
>> PLEASE do read the posting guide
>> http://www.R-project.org/posting-guide.html
>> and provide commented, minimal, self-contained, reproducible code.
> 
> David Winsemius, MD
> Heritage Laboratories
> West Hartford, CT
> 
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
> 
> 

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