Data::Dumper::SLC ?? What's that?

It's my own module that produces better formatted output than Data::Dumper. As it is only used to test that the tranformation is correct, it doesn't affect the OPs use of the algorithm demonstrated.

And were you intentionally ignoring the request that modules not be used?

That leaves only my use of List::Util::max. Which, as it has been a part of the core for a while now, the possibility is that the OP would have access to it without an additional installation. If not, then the OP only has to ask here how write an equivalent function, or read the source of the pure perl version of L::U, if they don't know how to do that already.

Feel free to consider the node for removal if this explaination doesn't satisfy.

Feel free to consider the node for removal if this explaination doesn't satisfy.

?? Sorry, I wasn't trying to complain (though rereading my note, it certainly sounds like a complaint). I was honestly curious whether you were intentionally or unintentionally using modules. If I hadn't had the question about DDSLC I wouldn't have even bothered posting.

Let me try again:

I see you are using some modules though the OP is looking for a solution that doesn't do so. More power to your elbow! A perl programmer without modules is like a shell programmer without a keyboard! (Well, not quite.) But did you miss that part of the OP? Or just ignore it but not want to bring up the same old discussion that comes up whenever anybody claims they "aren't allowed to use modules"? Or other?

But did you miss that part of the OP? Or just ignore it but not want to bring up the same old discussion that comes up whenever anybody claims they "aren't allowed to use modules"? Or other?

I didn't miss it.

I (rightly or wrongly) assumed that the OP wasn't interested in installing any new modules in order to effect the transformation. Eg. one of the many Set::* or Matrix::* modules that probably exist. In other words, I didn't view the OPs question as a "Can you do this without the use of any modules whatsoever?" challenge.

I didn't think about the why of the restriction for two reasons.

• Often as not, those type of modules are OO-style; impose their own intermediate storage format on the data; often have a not insignificant learning curve.

  To me, this is like buying one of those 1000 piece toolkits in order to get a hammer to crack a nut. If the application requires extensive use of matrix manipulations, then installing and using one of those modules makes sense, but for the OPs task, overkill.

• I've worked at many sites where the in-house rules seemed stupid to me, but I had to comply with them regardless of my opinions.

  The OP knows their situation best and Yet Another Extended Discussions on the merits or otherwise of "Approved modules only" policies seemed to have no merit to me.

  ---

  With respect to D::D:SLC.

  If I thought that there would be sufficient demand for a Dumper only module, then I might go through the process of producing documentation (fairly easy as it has only three parameters, but even that would require me to write POD which I find an exercise in total frustration), and packaging it for CPAN.

  But previous threads here at the Monastery with respect to this subject suggested to me that the demand does not exist. Indeed, just my asking if such a module did exist, drew so much ire that I thought is best not to mention it again.

  I also don't think it's mature enough yet. I still encounter occasional bugs--though not for a while--and I am of the opinion that modules become candidates for CPAN when they have prooved themselves useful and stable for their authors. Not because someone decided that they needed to have a presence on CPAN.

  Not a universally accepted opinion I know, so I don't usually express it, but I try to live by what I think.

  ---

  Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

  Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?

  "Science is about questioning the status quo. Questioning authority".

  The "good enough" maybe good enough for the now, and perfection maybe unobtainable, but that should not preclude us from striving for perfection, when time, circumstance or desire allow.