data.table in R: Why can't data.table::`:=`() be called? -


use dt = data.table(type=rep(c("b","a"),each=2), value=1:4) create following data.table:

   type value 1:    b     1 2:    b     2 3:        3 4:        4

the code dt[, `:=`(text=max(value)), by=type] works well:

   type value test 1:    b     1    2 2:    b     2    2 3:        3    4 4:        4    4

same code (except data.table:: calling part) dt[, data.table::`:=`(text=max(value)), by=type] doesn't work , returns following error:

error in data.table::`:=`(text = max(value)) :    check is.data.table(dt) == true.    otherwise, := , `:=`(...) defined use in j,    once , in particular ways.    see help(":=").

can tell me why can't call := function data.table::`:=`() can call other functions data.table data.table::data.table?

please me, want use data.table::`:=`() in package.

many ahead!


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