Hi there, I have just installed the new version of data.table and used the "fresh" function combining *:= in j *with *by*, and I am very happy with it. So first I want to thank the maintainers/developers for the library and the new function.
The main reason for my email, though, is the following: I had a variable called results62. I created a column of NAs called LAGMKTCAP and subsequently tried to change the values of this column using results62[,LAGMKTCAP := results62$MKTCAP[match(results62$PM,results62$TM)],by=PERMNO] without having created the column TM beforehand. I received the output from R of the head and tail of my object results62, as expected, but the column LAGMKTCAP hadn't been changed. Only later did I realise I had forgotten to create the column TM. Wouldn't it be desirable to return an error when trying to use a column of the data.table object which doesn't yet exist? Is this normal behaviour or a bug? Vivianne ---------------------------------------------- “Don't worry about the world coming to an end today. It is already tomorrow in Australia.”
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