[R] Replace values in data.frame conditional on another data.frame

[John Kane]

Try 
bb[is.na(aa)] <- NA

It may be simple but it is not necessarily obvious :)
--- Carson Farmer <cfarmer at uvic.ca> wrote:

> Dear List,
> 
> I am looking for an efficient method for replacing
> values in a
> data.frame conditional on the values of a separate
> data.frame. Here is
> my scenario:
> I have a data.frame (A) with say 1000 columns, and
> 365 rows. Each cell
> in the data.frame has either valid value, or NA. I
> have an additional
> data.frame (B) with the same number of rows and
> columns, with valid
> values in all cells. What I would like to do, is
> replace the cells in B
> with NA if and only if the corresponding cell in A
> is NA.
> I have search extensively for a method to do this,
> and I'm sure that in
> the end the solution will be embarrassingly simple,
> however, any help is
> greatly appreciated!
> 
> Cheers,
> 
> Carson
> 
> Apologies if this has been posted twice, we are
> currently experiencing 
> server problems...
> 
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