R help - Jul 2009 - is a sequence of dates consecutive, without gaps?

On Jul 21, 2009, at 4:58 PM, Christopher W. Ryan wrote:
> I have a long sequence of dates, about 6 years worth, as one column  
> in a
> data frame. How can I test whether the sequence is consecutive, that  
> is,
> without gaps?
>
> Thanks.
>
> --Chris

Chris,

Presuming that your data frame is called DF, the date column is called  
'date' AND 'date' has been coerced to a Date class, you could
use:

   all(diff(DF$date) == 1)

which will tell you if all of the differences between successive dates  
in the column are one day.

See ?diff for more information.

If the dates have not yet been coerced to a Date class, see ?as.Date.

HTH,

Marc Schwartz

I have a long sequence of dates, about 6 years worth, as one column in a
data frame. How can I test whether the sequence is consecutive, that is,
without gaps?

Thanks.

--Chris
-- 
Christopher W. Ryan, MD
SUNY Upstate Medical University Clinical Campus at Binghamton
40 Arch Street, Johnson City, NY  13790
cryanatbinghamtondotedu

"If you want to build a ship, don't drum up the men to gather wood,
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