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From: Todd A. Jacobs on 3 Jun 2010 12:04
Ruby has a terrific implementation of single-valued permutations, but it
doesn't yield the results I expected when using arrays of arrays. For
example:

[[1, 2], [2, 3]].permutation.to_a.include? [2, 1]
=> false

The reason is that there's no permutation of the sub-arrays, just of the
top-level array elements. Am I overlooking something obvious here? I'd
like the permutations to include randomization within each sub-array,
too.

--
"Oh, look: rocks!"
-- Doctor Who, "Destiny of the Daleks"

From: botp on 3 Jun 2010 12:59
On Fri, Jun 4, 2010 at 12:04 AM, Todd A. Jacobs
<tjacobs-sndr-019fdb(a)codegnome.org> wrote:
> The reason is that there's no permutation of the sub-arrays, just of the
> top-level array elements.

you assumed that it has *only* sub-arrays

consider eg,
[[1, 2], :a, String, 3].permutation.to_a

> Am I overlooking something obvious here? I'd
> like the permutations to include randomization within each sub-array,

just include permutation of the sub then

kind regards -botp

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