R help - Jul 2009 - apply/return and reuse

Hi,
   Is it possible to make something like the following code actually
work? My goal in this example would be that I'd see results like

1   10000   10100
2   10100   10200
3   10200   10300
4   10300   10400

In real usage the function would obviously do a lot more work, but the
question I cannot answer myself yet is whether the apply can return a
value from the work on one row and then use that value as the input to
the function for the next row?

Thanks,
Mark


ReturnLast = function (.row, NextInitial=100) {
   .row$Initial = as.numeric(NextInitial)
   .row$Final = as.numeric(.row$Initial+100)
}

MyStart = 10000
X = data.frame(cbind(Event = 1:10, Initial = 0, Final = 0))

X

MyStart  = apply(X, 1, ReturnLast( X, MyStart))

X

See ?Reduce

On Fri, Jul 17, 2009 at 11:10 PM, Mark Knecht<markknecht at gmail.com>
wrote:
> Hi,
> ? Is it possible to make something like the following code actually
> work? My goal in this example would be that I'd see results like
>
> 1 ? 10000 ? 10100
> 2 ? 10100 ? 10200
> 3 ? 10200 ? 10300
> 4 ? 10300 ? 10400
>
> In real usage the function would obviously do a lot more work, but the
> question I cannot answer myself yet is whether the apply can return a
> value from the work on one row and then use that value as the input to
> the function for the next row?
>
> Thanks,
> Mark
>
>
> ReturnLast = function (.row, NextInitial=100) {
> ? .row$Initial = as.numeric(NextInitial)
> ? .row$Final = as.numeric(.row$Initial+100)
> }
>
> MyStart = 10000
> X = data.frame(cbind(Event = 1:10, Initial = 0, Final = 0))
>
> X
>
> MyStart ?= apply(X, 1, ReturnLast( X, MyStart))
>
> X
>
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