Well, it’s rather simple, but maybe there is already a built-in function to do calculate this? natural_length(s) = s[end]-s[begin] natural_length((1,10)) natural_length((1:10)) It annoying to copy-paste this snippet which is not large enough to bother putting it into a package.

[image] mkitti: This does not work for all iterators. Even last(a) - first(a) seems wrong to me for a non-sorted iterator. A more general solution would be to use the extrema function : diameter(itr) = -(reverse(extrema(itr))...) which is equivalent to the more verbose (but more readable) …

It seems quite specific so I doubt there is a built-in function (I might be wrong though). However, last(x) - first(x) seems short enough and self-explanatory.

Well, it’s more or less the same as my function.

Yes (last/first might be a tiny bit more performant). I wanted to point it out in case you disliked the indexing in your function.

Or maybe there is something like diameter for sets that can be applied to iterators?

This does not work for all iterators. julia> g = (i for i in 2:10) Base.Generator{UnitRange{Int64}, typeof(identity)}(identity, 2:10) julia> natural_length(x) = x[end] -x[begin] natural_length (generic function with 1 method) julia> natural_length(g) ERROR: MethodError: no method matching lastind…

[image] mkitti: This does not work for all iterators. Huh, yet another difference to first/last; they are defined for more types, including your example. (Btw. diff, on the other hand, is not defined for tuples.)

Some variations of the same idea diamet(itr) = -(-(extrema(itr)...)) diameter(itr) = [-1 1]*[extrema(itr)...]

[image] stevengj: diameter(itr) = -(reverse(extrema(itr))...) That’s neat. [image] stevengj: So, I don’t think there is much need for a built-in (or package) function to compute diameter, since computing diameter is a one-liner given extrema. Well, length is also a one-liner that “def…

[image] homocomputeris: Well, length is also a one-liner that “defaults to prod(size(A))”, and it’s ever shorter than -(reverse(extrema(itr))...), yet it’s included into the stdlib. Because it’s an extraordinarily common function to call. diameter as defined here does not seem to be commonly…

[image] stevengj: Is there any language that provides such a function in its standard library? If we include Numpy, I think it’s numpy.ptp (“peak to peak”).

Is there a built-in function for the natural length of a segment represented by an iterator?

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Is there a built-in function for the natural length of a segment represented by an iterator?

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