NA as a factor level malformed by rbindlist #3915

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1. jangorecki commented on Sep 26, 2019

   

   jangorecki

   on Sep 26, 2019

   Last edited by jangorecki

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   Same in devel. Thanks for reporting. Happens when printing DT having > 100 rows because of head&tail print format.

   root cause of the issue is rbindlist in this line

   data.table/R/print.data.table.R

   Line 61 in 5ab1884

   toprint = rbindlist(list(head(x, topn), tail(x, topn)), use.names=FALSE) # no need to match names because head and tail of same x, and #3306

   producing malformed factor, so the issue is actually in rbindlist. fyi @mattdowle
   minimal example

   x = data.table(V1 = factor(as.character(c(NA, 1:3, NA)), exclude = NULL))
   rbindlist(list(x), use.names=FALSE)$V1
   #Error in as.character.factor(x) : malformed factor

   👍React with 👍1Reacted by Matt Dowle
2. jangorecki

   self-assigned this

   on Sep 26, 2019
3. jangorecki

   added this to the 1.12.4 milestone on Sep 26, 2019
4. jangorecki

   assigned

   mattdowle

   and unassigned

   jangorecki

   on Sep 26, 2019
5. jangorecki

   changed the title [-]NA as a factor level in a data.table column[/-] [+]NA as a factor level malformed by rbindlist[/+] on Sep 26, 2019
6. mattdowle

   added a commit that references this issue on Sep 26, 2019

   rbindlist malformed NA factor level, #3915

   2be417d
7. mattdowle

   closed this as completedin #3909on Sep 28, 2019