search

epiforecasts / scoringutils

Utilities for Scoring and Assessing Predictions
https://epiforecasts.io/scoringutils/
Other
48 stars 21 forks source link

Data.table issue: shallow copies created when manipulating `scores` objects #931

Closed nikosbosse closed 1 month ago

nikosbosse commented 1 month ago

reprex: 

ex <- score(example_quantile)
ex[, n_samples := 3]

produces

Warning message:
In `[.data.table`(ex, , `:=`(n_samples, 3)) :
  Invalid .internal.selfref detected and fixed by taking a (shallow) copy of the data.table so that := can add this new column by reference. At an earlier point, this data.table has been copied by R (or was created manually using structure() or similar). Avoid names<- and attr<- which in R currently (and oddly) may copy the whole data.table. Use set* syntax instead to avoid copying: ?set, ?setnames and ?setattr. If this message doesn't help, please report your use case to the data.table issue tracker so the root cause can be fixed or this message improved.

I think the issue is due to the use of attr in 

`[.scores` <- function(x, ...) {
  ret <- NextMethod()
  if (is.data.frame(ret)) {
    attr(ret, "metrics") <- attr(x, "metrics")
  }
  return(ret)
}