convert a data frame with NULL to a list of integer

I have a data frame with integers mixed with a lot of NULLs, how do I convert
that to multiple lists of integers with zero (to replace NULL)? I tried the
following, and they failed:

dim(g2)

[1] 25352   173

class(g2)

[1] "data.frame"

class(g2[1,])

[1] "data.frame"

g2[1,30:40]

30 31 32   33 34 35 36   37   38   39   40
NM_000014  1 14  1 NULL 27  8 21 NULL NULL NULL NULL

g3<-as.integer(g2[1,30:40])
g3

[1] NA NA NA NA NA NA NA NA NA NA NA

thanks a lot!

-Kenny

View this message in context: http://n4.nabble.com/convert-a-data-frame-with-NULL-to-a-list-of-integer-tp1445595p1445595.html
Sent from the R help mailing list archive at Nabble.com.