R help - Apr 2009 - How to preserve NULL in vector

I have a vector containing NULL. Referencing to that NULL gives me NA
instead, which disrupt my codes. How can i preserve NULL as it is ?
> res <- c(1,2,NULL)
> res[1]
[1] 1
> res[2]
[1] 2
> res[3]
[1] NA

On 4/6/2009 9:24 AM, Daren Tan wrote:
> I have a vector containing NULL. Referencing to that NULL gives me NA
> instead, which disrupt my codes. How can i preserve NULL as it is ?
NULL is not a numeric value, so you can't put it in a numeric vector. 
When you tried, it got converted to the numeric value NA.

You can have a list containing NULL, and lists are vectors, but 
functions that expect *numeric* vectors generally won't work with them.

Duncan Murdoch
> 
>> res <- c(1,2,NULL)
>> res[1]
> [1] 1
>> res[2]
> [1] 2
>> res[3]
> [1] NA
> 
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