[R] Subset and order

[Noah Silverman]

That would work, but is painfully slow.  It forces a new sort of the data with every query.  I have 200,000 rows and need almost a hundred queries.

Thanks,

-N


On Jul 5, 2013, at 12:43 PM, Rui Barradas <ruipbarradas at sapo.pt> wrote:

> Hello,
> 
> Maybe like this?
> 
> subset(x[order(x$a), ], b == 3)
> 
> 
> Hope this helps,
> 
> Rui Barradas
> 
> Em 05-07-2013 20:33, Noah Silverman escreveu:
>> Hello,
>> 
>> I have a data frame with several columns.
>> 
>> I'd like to select some subset *and* order by another field at the same time.
>> 
>> Example:
>> 
>> a	b	c
>> 1	2	3
>> 3	3	4
>> 2	4	5
>> 1	3	4
>> etc…
>> 
>> 
>> I want to select all rows where b=3 and then order by a.
>> 
>> To subset is easy:  x[x$b==3,]
>> To order is easy: x[order(x$a),]
>> 
>> Is there a way to do both in a single efficient statement?
>> 
>> Thanks,
>> 
>> 
>> 
>> --
>> Noah Silverman, M.S., C.Phil
>> UCLA Department of Statistics
>> 8117 Math Sciences Building
>> Los Angeles, CA 90095
>> 
>> 
>> 
>> 
>> 	[[alternative HTML version deleted]]
>> 
>> 
>> 
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