R help - Nov 2008 - Returning a vector from by

Hello,

I am trying to return a vector from a simply by but I cannot get it
working, even using simplify=TRUE.

res <-
data.frame(ID=c("a","a","a","b","b"),Score=c(0,1,2,0,1))
yoda <- by(res$Score,res$ID,max,simplify=T)
class(yoda)
[1] "by"

I would like it to return a vector with the names as the ID column.  The
only way I could work out how to do this was

result <- as.vector(yoda)
names(result) <- names(yoda)
result
a b
2 1

Is there a better way?

Thanks

Dan

-- 
**************************************************************
Daniel Brewer, Ph.D.

Institute of Cancer Research
Molecular Carcinogenesis
Email: daniel.brewer at icr.ac.uk
**************************************************************

The Institute of Cancer Research: Royal Cancer Hospital, a charitable Company
Limited by Guarantee, Registered in England under Company No. 534147 with its
Registered Office at 123 Old Brompton Road, London SW7 3RP.

This e-mail message is confidential and for use by the a...{{dropped:2}}

If you just want that result, you can try tapply instead of by.
> tapply(res$Score,res$ID,max)
a b
2 1

On Mon, Nov 3, 2008 at 7:31 PM, Daniel Brewer <daniel.brewer at icr.ac.uk>
wrote:
> Hello,
>
> I am trying to return a vector from a simply by but I cannot get it
> working, even using simplify=TRUE.
>
> res <-
data.frame(ID=c("a","a","a","b","b"),Score=c(0,1,2,0,1))
> yoda <- by(res$Score,res$ID,max,simplify=T)
> class(yoda)
> [1] "by"
>
> I would like it to return a vector with the names as the ID column.  The
> only way I could work out how to do this was
>
> result <- as.vector(yoda)
> names(result) <- names(yoda)
> result
> a b
> 2 1
>
> Is there a better way?
>
> Thanks
>
> Dan
>
> --
> **************************************************************
> Daniel Brewer, Ph.D.
>
> Institute of Cancer Research
> Molecular Carcinogenesis
> Email: daniel.brewer at icr.ac.uk
> **************************************************************
>
> The Institute of Cancer Research: Royal Cancer Hospital, a charitable
Company Limited by Guarantee, Registered in England under Company No. 534147
with its Registered Office at 123 Old Brompton Road, London SW7 3RP.
>
> This e-mail message is confidential and for use by the...{{dropped:19}}

Hi

r-help-bounces at r-project.org napsal dne 03.11.2008 12:31:31:
> Hello,
> 
> I am trying to return a vector from a simply by but I cannot get it
> working, even using simplify=TRUE.
> 
> res <-
data.frame(ID=c("a","a","a","b","b"),Score=c(0,1,2,0,1))
> yoda <- by(res$Score,res$ID,max,simplify=T)
> class(yoda)
> [1] "by"
> 
> I would like it to return a vector with the names as the ID column.  The
> only way I could work out how to do this was
> 
> result <- as.vector(yoda)
> names(result) <- names(yoda)
> result
> a b
> 2 1
Maybe tapply?

yoda <- tapply(res$Score,res$ID,max,simplify=T)

Regards

Petr
> 
> Is there a better way?
> 
> Thanks
> 
> Dan
> 
> -- 
> **************************************************************
> Daniel Brewer, Ph.D.
> 
> Institute of Cancer Research
> Molecular Carcinogenesis
> Email: daniel.brewer at icr.ac.uk
> **************************************************************
> 
> The Institute of Cancer Research: Royal Cancer Hospital, a charitable 
Company 
> Limited by Guarantee, Registered in England under Company No. 534147 
with its 
> Registered Office at 123 Old Brompton Road, London SW7 3RP.
> 
> This e-mail message is confidential and for use by the a...{{dropped:2}}
> 
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