R help - May 2007 - subset arg in (modified) evalq

Hi, 

When using evalq to evaluate expressions within a say data.frame context I often
wish there was a 'subset' argument, much like in lm() or any ather
advanced regression model. I would be grateful for a tip how to do this.

Here is an illustration of what I want: 

n <- 100 
data <- data.frame(x=rnorm(n), y=rnorm(y), z=rnorm(z)) 

# this works 
evalq({ i <- 0<x; summary(y[i] + z[i]) }, data) 

# I want to do the above w/o explicit subscripting, e.g. 
myevalq(summary(y + z), subset=0<x, data) 

Thanks, 
Vadim 

	[[alternative HTML version deleted]]

Try this:

   with(subset(data, x > 0), summary(y + z))


On 5/18/07, Vadim Ogranovich <vogranovich at jumptrading.com>
wrote:
> Hi,
>
> When using evalq to evaluate expressions within a say data.frame context I
often wish there was a 'subset' argument, much like in lm() or any ather
advanced regression model. I would be grateful for a tip how to do this.
>
> Here is an illustration of what I want:
>
> n <- 100
> data <- data.frame(x=rnorm(n), y=rnorm(y), z=rnorm(z))
>
> # this works
> evalq({ i <- 0<x; summary(y[i] + z[i]) }, data)
>
> # I want to do the above w/o explicit subscripting, e.g.
> myevalq(summary(y + z), subset=0<x, data)
>
> Thanks,
> Vadim
>
>        [[alternative HTML version deleted]]
>
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