[R] extracting names from matrix according to a condition

[ivan]

thank you very much. worked great for me.

On Mon, Apr 25, 2011 at 8:22 PM, Peter Ehlers <ehlers at ucalgary.ca> wrote:
> On 2011-04-25 10:58, ivan wrote:
>>
>> Dear Community,
>>
>> I have a matrix with assigned colnames and rolnames as follows:
>>
>>             A            B
>> NR    0.15      0,05
>> AL     0,05      0,05
>> .           .            .
>> .           .            .
>> .           .            .
>>
>> I want to extract the names of the rows for which A>0,1 and B<0,1. In
>> the above example this would be observation NR only. Hence the output
>> should write for instance:
>>
>> names:
>> NR
>>
>> Is this possible? Thank you very much for your help.
>
> Call the matrix m. Then
>
>  rownames(m[ m[, "A"] > 0.1 & m[, "B"] < 0.1, , drop=FALSE ])
>
> should do what you want.
>
> Peter Ehlers
>