[R] problems subsetting

[Martin Tomko]

Thanks Steve, that explains it... Unfortunately, I did nto get that from 
my R docs...

I am still searching for a solution for matching the entries in my 
matrix by matching the rownames to the entires in a subset I got using 
Gerrit's method.

Any idea?
Thanks
Martin

On 11/18/2010 4:35 PM, Steve Lianoglou wrote:
> Hi,
>
> On Thu, Nov 18, 2010 at 10:25 AM, Martin Tomko<martin.tomko at geo.uzh.ch>  wrote:
>    
>> Hi Gerrit,
>> indeed, that works. Excellent tip!
>>
>> For reference, I did this:
>>
>> subset1<-subset(summarystats,(Type==1)&(Class==1)&(Category==1))
>>
>> I am still not totally sure when one uses "&" amd when"&&"  - I was under
>> the impression that&&  stands for logical AND....
>>      
> If you can't find the appropriate documentation, try to experiment in
> your workspace:
>
> R>  c(TRUE, TRUE, FALSE, TRUE)&  c(FALSE, TRUE, TRUE, TRUE)
> [1] FALSE  TRUE FALSE  TRUE
>
> R>  c(TRUE, TRUE, FALSE, TRUE)&&  c(FALSE, TRUE, TRUE, TRUE)
> [1] FALSE
>
> The single logical operators (&  , |) run over the entire length of
> your logical vectors.
> The doubles (&&, ||) just evaluate the first element of the vectors,
> and ignore the rest.
>
>