Improvement: function cut

While it is not explicitly mentioned anywhere in the documentation for 
.bincode, I suspect 'include.lowest = FALSE' is the default to keep 
the definitions of the bins consistent. For example:


x <- 0:20
breaks1 <- seq.int <http://seq.int>(0, 16, 4)
breaks2 <- seq.int <http://seq.int>(0, 20, 4)
cbind(
? ? .bincode(x, breaks1, right = FALSE, include.lowest = TRUE),
? ? .bincode(x, breaks2, right = FALSE, include.lowest = TRUE)
)


by having 'include.lowest = TRUE' with different ends, you can get 
inconsistent behaviour. While this probably wouldn't be an issue with 
'real' data, this would seem like something you'd want to avoid by 
default. The definitions of the bins are


[0, 4)
[4, 8)
[8, 12)
[12, 16]


and


[0, 4)
[4, 8)
[8, 12)
[12, 16)
[16, 20]


so you can see where the inconsistent behaviour comes from. You might 
be able to get R-core to add argument 'warn', but probably not to 
change the default of 'include.lowest'. I hope this helps


On Fri, Sep 17, 2021 at 6:01 PM Leonard Mada <leo.mada at syonic.eu 
<mailto:leo.mada at syonic.eu>> wrote:

    Thank you Andrew.


    Is there any reason not to make: include.lowest = TRUE the default?


    Regarding the NA:

    The user still has to suspect that some values were not included
    and run that test.


    Leonard


    On 9/18/2021 12:53 AM, Andrew Simmons wrote:

    Regarding your first point, argument 'include.lowest' already
    handles this specific case, see ?.bincode

    Your second point, maybe it could be helpful, but since both
    'cut.default' and '.bincode' return NA if a value isn't within a
    bin, you could make something like this on your own.
    Might be worth pitching to R-bugs on the wishlist.



    On Fri, Sep 17, 2021, 17:45 Leonard Mada via R-help
    <r-help at r-project.org <mailto:r-help at r-project.org>> wrote:

        Hello List members,


        the following improvements would be useful for function cut
        (and .bincode):


        1.) Argument: Include extremes
        extremes = TRUE
        if(right == FALSE) {
        ??? # include also right for last interval;
        } else {
        ??? # include also left for first interval;
        }


        2.) Argument: warn = TRUE

        Warn if any values are not included in the intervals.


        Motivation:
        - reduce risk of errors when using function cut();


        Sincerely,


        Leonard