I want to use column index in dcast in data.table:
dcast(setDT(x),rowid(X__9) ~ X__9,value.var = "count")
Above works fine,but column name X__9
is dynamic it may change to X__7
or X__8
. How can we pass column index 1
to dcast so that every time it will work irrespective of dynamic column names. I tried:
dcast(setDT(x),rowid(names(.)[1]) ~ names(.)[1],value.var = "count")
But it does not work.