[R-sig-Geo] making sequential subsets of a ppp object, based on value of a mark

[Christopher W. Ryan]

Ah, it's split(), of course. That was silly of me.

--Chris Ryan

Christopher W. Ryan wrote:
> I have a marked ppp object, about 5300 points. One of the marks is
> called period and has values 1:13.  What is an efficient way to make 13
> period-specific subset point patterns?  All I've been able to come up
> with, embarrasingly, is 13 lines like the following:
> 
> per1.ppp <-  subset(analytical.ppp, subset = (period == 1))
> pre2.ppp <-  subset(analytical.ppp, subset = (period == 2))
> per3.ppp <-  subset(analytical.ppp, subset = (period == 3))
> and so on.
> 
> I'm sure there is a better way.
> 
> Thanks.
> 
> --Chris Ryan
>