data$ID -> I always get a NULL
On Apr 20, 2009, at 4:33 AM, Grze? 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, 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
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