We can define span(x) another way:
span(x) = max {|a-b| | a \in x, b \in x}
This gives the same result as diff(range(x)) for logical x, integer x,
and double x, but it also works for complex x and in general for any
collection of elements of something that could be seen as a normed
vector spans.
This makes a good example of why it might be a bad idea to jump
prematurely to a definition in base R.
But there is another and more obviously statistical reason. Consider
a time series.
diff(range(..)) makes sense on a (real, complex, multivariate) time
series, but the span of a time series
is more usually thought of as the span of *time* it is measured over.
On Thu, 26 Jun 2025 at 06:11, Dennis Fisher <fis...@plessthan.com> wrote:
>
> Version 4.4.2
> OS X
>
> Colleagues
>
> I often need to determine the span of the x-variable in a graphic.
>
> This is easy to determine with:
> diff(range(VAR, na.rm=T))
>
> I am not aware of any function in base R that accomplishes this and “span” is
> not taken.
>
> Would it be possible to add such a function? Not a major addition but often
> useful.
>
> Dennis
>
> Dennis Fisher MD
> P < (The "P Less Than" Company)
> Phone: 1-415-307-4791
> www.PLessThan.com
>
>
> [[alternative HTML version deleted]]
>
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