R help - Mar 2013 - help on extracting values from a matrix

Dear All,
 
any thoughts on how I can do the following:
 
let us say we have:
 
a <-c(2,4,16,28,48)
b <-c(10,4,2,0.4,0.03)
d <-cbind(a,b)
 
what I would like to do is to extract values of column b in the matrix based on
the corresponding values of column a. For example: I would like to extract all b
values that have a corresponding a value that is less than 24 into a numeric
vector, so let us say we name this new vector f, then the results should look
like:
 
f <-c(10,4,2)
 
as allways your help is greatly appreciated, 
 
Andras
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Hi,

Well, simply :

d[a<24,2]

should do the trick.

Pierrick Bruneau
CRP Gabriel Lippmann


On Wed, Mar 20, 2013 at 12:53 PM, Andras Farkas <motyocska@yahoo.com>
wrote:
> Dear All,
>
> any thoughts on how I can do the following:
>
> let us say we have:
>
> a <-c(2,4,16,28,48)
> b <-c(10,4,2,0.4,0.03)
> d <-cbind(a,b)
>
> what I would like to do is to extract values of column b in the matrix
> based on the corresponding values of column a. For example: I would like to
> extract all b values that have a corresponding a value that is less than 24
> into a numeric vector, so let us say we name this new vector f, then the
> results should look like:
>
> f <-c(10,4,2)
>
> as allways your help is greatly appreciated,
>
> Andras
>         [[alternative HTML version deleted]]
>
>
> ______________________________________________
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>
>
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