Now everything is clear for me. Thanks David! :)
David Winsemius wrote: > > > On Apr 20, 2009, at 4:33 AM, Grześ wrote: > >> >> 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 > > So the names of your columns are not "ID" and "kod" but rather "X.ID." > and "X.kod." > > Try instead: > data$X.ID. > #and: > data$X.kkod. # you will need to use both the periods if your > column names end in periods. > > >>>> >>>> but command like below is always recognize by R >>>>> data[2,3] >>>> [1] '082' > > > That must have been a different version of data, since data[2,3] from > the dataframe above should have been the number 7 number rather > than a string. I would also suggest that you start naming your > data.frames something other than "data", since that is a reserved word > used by quite a few functions. > > >>>> >>> >>> 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? >>>> > >>>> -- > > David Winsemius, MD > Heritage Laboratories > West Hartford, CT > > ______________________________________________ > R-help@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. > > -- View this message in context: http://www.nabble.com/data%24ID--%3E-I-always-get-a-NULL-tp23128214p23139208.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ R-help@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.
