R help - Nov 2010 - Count continuous dates

Dear List,

I have a series of dates and I am needing to know the greatest length of 
continuous dates - i.e. the number of dates before a break in the series.? For 
example, below there are three continuous series of dates with lengths 4, 6, and
8.? How can I count the number of continuous dates?? rle() will do it for 
constant integers, but I can't figure a way to modify it for continuous
dates.

x<-c("1/10/10","2/10/10","3/10/10","4/10/10",
????
"6/10/10","7/10/10","8/10/10","9/10/10","10/10/10","11/10/10",
???? 
"13/10/10","14/10/10","15/10/10","16/10/10","17/10/10","18/10/10","19/10/10","20/10/10")

x<-strptime(x,"%d/%m/%y")



Thanks!

Tim
?Tim Clark
Marine Ecologist
National Park of American Samoa
Pago Pago, AS 96799

Hi Tim,

Thanks for providing nice sample data!  It made this super easy :)

## use diff() to find the differences
## use rle() to find the run lengths
## use max to find the highest one
max(rle(as.vector(diff(x)))$lengths)


Cheers,

Josh

On Wed, Nov 10, 2010 at 10:07 PM, Tim Clark <mudiver1200 at yahoo.com>
wrote:
> Dear List,
>
> I have a series of dates and I am needing to know the greatest length of
> continuous dates - i.e. the number of dates before a break in the series.?
For
> example, below there are three continuous series of dates with lengths 4,
6, and
> 8.? How can I count the number of continuous dates?? rle() will do it for
> constant integers, but I can't figure a way to modify it for continuous
dates.
>
>
x<-c("1/10/10","2/10/10","3/10/10","4/10/10",
> ????
"6/10/10","7/10/10","8/10/10","9/10/10","10/10/10","11/10/10",
>
>
"13/10/10","14/10/10","15/10/10","16/10/10","17/10/10","18/10/10","19/10/10","20/10/10")
>
> x<-strptime(x,"%d/%m/%y")
>
>
>
> Thanks!
>
> Tim
> ?Tim Clark
> Marine Ecologist
> National Park of American Samoa
> Pago Pago, AS 96799
>
>
>
>
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>

-- 
Joshua Wiley
Ph.D. Student, Health Psychology
University of California, Los Angeles
http://www.joshuawiley.com/