R help - Dec 2008 - Problems with large data frames?

Hi,

I recently added another 1,000 observations to a data frame I have for  
a total of 10,861 observations.  Observations are by row and the frame  
has 15 columns.  R now keeps converting certain columns to factors  
whenever I run regressions and can't seem to figure out the correct  
scaling for the axes of plots on its own.

Are these problems the result of the size of my data frame or  
something else?  I can't see anything wrong with the data itself.  Any  
ideas what might be causing these recent problems and any way to force  
R not to convert variables to factors?

- Chris

If it converts into a factor although it appears to be numeric, then there
is probably a string entry somewhere in this variable, which causes R to
convert the whole variable into a factored variable (which results in
dummies in the regression). You will want to check whether there are any
excess delimiters (spaces or what not) in the observations that you have
added. 

Say x is your variable. Do

is(x)

before and after adding the 1000 observations. If x is numeric before and
factor after adding the observations, then it tells you that the above
mentioned problem exists in the added observations.

Best,
Daniel

-------------------------
cuncta stricte discussurus
-------------------------

-----Urspr?ngliche Nachricht-----
Von: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] Im
Auftrag von Chris Poliquin
Gesendet: Saturday, December 13, 2008 2:23 AM
An: r-help at r-project.org
Betreff: [R] Problems with large data frames?

Hi,

I recently added another 1,000 observations to a data frame I have for a
total of 10,861 observations.  Observations are by row and the frame has 15
columns.  R now keeps converting certain columns to factors whenever I run
regressions and can't seem to figure out the correct scaling for the axes of
plots on its own.

Are these problems the result of the size of my data frame or something
else?  I can't see anything wrong with the data itself.  Any ideas what
might be causing these recent problems and any way to force R not to convert
variables to factors?

- Chris

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