Stephen Lake wrote:
Hi S-users,
Could someone please tell me how I can assign NA's to
character vectors and matrices? The usual element
assignment does not seem to work. Here is an example:
vec <- letters[1:5]
vec
[1] "a" "b" "c" "d" "e"
vec[4] <- NA
vec
[1] "a" "b" "c" "NA" "e"
is.na(vec)
[1] F F F F F
If instead of letters[1:5] I assign the numeric vector
1:5, the behavior is as expected, ie the is.na() function
detects a NA at position 4 of the vector.
Any help would be greatly appreciated,
Steve Lake
PS I am using Version 6.0 Release 1 for Sun SPARC, SunOS 5.5
From ?is.na:
REQUIRED ARGUMENTS:
x an S-PLUS object, which should be logical, numeric, or complex.
WARNING:
This is always FALSE when x is of mode "character".
You should use == "NA" if x is character. As in:
> vec <- letters[1:5]
> vec[4] <- NA
> vec == "NA"
[1] F F F T F
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