rbind.fill type casting - bug or feature? (plyr_1.8.3)

[markheckmann]

I found that a dataframe character vector when row binded consistently was converted to numbers. It turns out that rbind and rbind.fill behave differently (seems to be unwanted behaviour):

library(plyr)
d1 <- data.frame(a=NA, b=NA)
d2 <- data.frame(a="A", b=1)

rbind(d1, d2)
       a  b
  1 <NA> NA
  2   A  1

and different results for rbind.fill

rbind.fill(d1, d2)
     a  b
  1 NA NA
  2  1  1

which is different from standard vector type casting which gives

c(NA, "A")
NA  "A"

The same occurs for zero column data frames:

d3 <- data.frame(a=integer(), b=integer())

rbind(d3, d2)
   a b
 1 A 1

rbind.fill(d3, d2)
  a b
1 1 1

c(integer(), "A")
[1] "A"

If the type is the same, the results are the same:

d3 <- data.frame(a=character(), b=integer())

rbind(d3, d2)
  a b
1 A 1

rbind.fill(d3, d2)
  a b
1 A 1

[hadley]

d2 doesn't contain a character vector...

[markheckmann]

uups, of course, my mistake. TIL: do not work late night. okay, so rbind.fill handling is more in line with standard type R casting than rbind as c(NA, factor("A")) gives > NA 1. Thanks!

[hadley]

I only recognise it because it's happen to me so so so so many times