"Hiroto Miyoshi" <[EMAIL PROTECTED]> writes:
> Dear Professor Dalgaard
>
> > It is the NA pattern on the left hand side that matters. Does it help
> > to use
> >
> > seishin[!is.na(seishin) & seishin==""]<-NA
> >
> > ?
>
> Yes! the above line worked perfectly.
> But why? To me, !is.na(seishin) & seishin=="" seems redundant.
> If you could explain this, it would be greatly appreciated.
> Thank you.
It's due to this change (do check the NEWS file when things change
unexpectedly...):
o Subassignments involving NAs and with a replacement value of
length > 1 are now disallowed. (They were handled
inconsistently in R < 2.0.0, see PR#7210.) For data frames
they are disallowed altogether, even for logical matrix indices
(the only case which used to work).
Now, I'm getting slightly confused here, since there appears to be
exceptions:
> str(c)
`data.frame': 10 obs. of 2 variables:
$ a: Factor w/ 10 levels "1","10","2","3",..: 1 3 4 5 6 NA 8 9 10 2
$ b: Factor w/ 9 levels "","a","b","e",..: 2 3 1 NA 4 5 6 7 8 9
> c[c==""]<-NA
> str(c)
`data.frame': 10 obs. of 2 variables:
$ a: Factor w/ 10 levels "1","10","2","3",..: 1 3 4 5 6 NA 8 9 10 2
$ b: Factor w/ 9 levels "","a","b","e",..: 2 3 NA NA 4 5 6 7 8 9
> version
_
platform i686-pc-linux-gnu
arch i686
os linux-gnu
system i686, linux-gnu
status
major 2
minor 0.0
year 2004
month 10
day 04
language R
Also:
> aq <- airquality
> aq[aq==5] <- 98765432
> aq[aq==97] <- 98765432
Error: NAs are not allowed in subscripted assignments
(difference being that 97 occurs in columns with NA's and 5 does not)
--
O__ ---- Peter Dalgaard Blegdamsvej 3
c/ /'_ --- Dept. of Biostatistics 2200 Cph. N
(*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918
~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907
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