[R] rbind'ing empty rows in dataframes in 1.4.1 versus 1.5.0

[David Kane <David Kane]

Hi,

In 1.4.1, I was able to create extra "empty" rows in a dataframe as so:

> x <- data.frame(a = letters[1:3], b = 1:3)
> x
  a b
1 a 1
2 b 2
3 c 3
> x[4,]
    a  b
NA NA NA
> rbind(x, x[4,])
    a  b
1   a  1
2   b  2
3   c  3
NA NA NA
> R.version
         _                   
platform sparc-sun-solaris2.6
arch     sparc               
os       solaris2.6          
system   sparc, solaris2.6   
status                       
major    1                   
minor    4.1                 
year     2002                
month    01                  
day      30                  
language R                   

This does not work in 1.5.0

> x <- data.frame(a = letters[1:3], b = 1:3)
> x
  a b
1 a 1
2 b 2
3 c 3
> x[4,]
        a  b
<NA>     <NA> NA
> rbind(x, x[4,])
Error in if (nrow > 0 && all(ri == 1:ni)) seq(from = nrow + 1, length = ni) else ri : 
	missing value where logical needed
> R.version
         _                   
platform sparc-sun-solaris2.6
arch     sparc               
os       solaris2.6          
system   sparc, solaris2.6   
status                       
major    1                   
minor    5.0                 
year     2002                
month    04                  
day      29                  
language R                   

Note that, contrary to my first guess, this has nothing (?) to do with the new
NA in character vectors since I see the same behavior with numeric only
dataframes.

> x <- data.frame(a = 5:7, b = 1:3)
> x
  a b
1 5 1
2 6 2
3 7 3
> x[4,]
      a  b
<NA>   NA NA
> rbind(x, x[4,])
Error in if (nrow > 0 && all(ri == 1:ni)) seq(from = nrow + 1, length = ni) else ri : 
	missing value where logical needed


I didn't see anything in the NEWS about this change. Could someone please
explain what is going one? Any words of wisom about the "right" way to create
empty rows in dataframe (which I then fill in variable by variable later in the
program) would also be appreciated.

Thanks,

Dave Kane
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