Hi all, 
  I have a large data.frame, 1530 observation with 6 columns. I want to
merge a 7th column, a transformation of the response variable (hospital
admissions), namely 
trans<-sqrt(copd$admissions+0.25)
trans<-data.frame(trans)
And now when I do 
copd2<-merge(copd,trans)
(copd being my original data.frame), R either crashes or is taking an
extremely long time to do the computation. I had expected the
computation to be done almost instantly as I have done similar things in
R recently, however my system becomes very slow to the point of being
unusable. Would people expect this computation to take a long time? Most
of the data in the data.frame are just integers.
  I want to perform linear regression on the data trans, so I would like
it in the data.frame to save typing.
Any ideas?
 

Robin Williams
Met Office summer intern - Health Forecasting
robin.williams@metoffice.gov.uk 

 

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