[R] Why can't R understand if(num!=NA)?

[Berend Hasselman]

On 03-05-2013, at 17:24, jpm miao <miaojpm at gmail.com> wrote:

> I have a program, when I write
> 
> if(num!=NA)
> 
> it yields an error message.
> 

it?
What is unclear about the error message?

> However, if I write
> 
> if(is.na(num)==FALSE)
> 
> it works.
> 
> Why doesn't the first statement work?
> 

Read section 2.5 'Missing values" of the manual "An Introduction to R".

Berend


> Thanks,
> 
> Miao
> 
> 	[[alternative HTML version deleted]]
> 
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