[R] <NA> from cut.Date

Prof Brian Ripley ripley at stats.ox.ac.uk
Wed Sep 17 13:31:34 CEST 2014

On 17/09/2014 12:04, Benjamin Tyner wrote:
> Hello,
> I'm wondering if this is expected?

It is as documented!
>      > cut(structure(11111, class="Date"), structure(c(11100,11111),
> class="Date"))
>      [1] <NA>
>      Levels: 2000-05-23
> The help page says that "for ‘"Date"’ objects, only ‘"day"’, ‘"week"’,
> ‘"month"’, ‘"quarter"’ and ‘"year"’ are allowed" [for the 'breaks'
> argument]. Though I am not sure whether this statement is only
> applicable in the context of the previous sentence about interval
> specification (i.e., a roundabout way of saying that ‘"sec"’, ‘"min"’,
> ‘"hour"’, and ‘"DSTday"’ are not allowed for 'Date' objects), or whether
> it also means that a vector of cut points (as in my example) is likewise
> not allowed? If the latter, then perhaps the function out to error out
> rather than return <NA> in this case?

The NA is correct: the value you pass is not covered by the 'breaks' you 
specified.  As the help says

      Using both ‘right = TRUE’ and ‘include.lowest = TRUE’ will include
      both ends of the range of dates.

With the default values, only the lower end is included.

Brian D. Ripley,                  ripley at stats.ox.ac.uk
Emeritus Professor of Applied Statistics, University of Oxford
1 South Parks Road, Oxford OX1 3TG, UK

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