[R] merge question

[Rolf Turner]

On 30/06/14 10:32, Dr Eberhard W Lisse wrote:

> Thanks,
>
> I then set NA to 0, and can do the sutraction,
>
> great.

Not so great.  I haven't gone through the issues underlying this post, 
but replacing NA by 0 will almost surely yield nonsense.  "Missing" is 
***not*** the same thing as "zero".  Pretending that it is will have 
disastrous consequences.  Think through what you are trying to do more 
clearly.

cheers,

Rolf Turner