'lo again...

I've been trying to find an algorithm to produce all the permutations for a subset of a group of items.

I've searched through my books, the web, all my code and have not found anything useful. I've searched this site and have found many articles that discuss the process in general... but these discussions nearly exclusively talk about various modifications to Algorithm::Permute, which is not suitable, as it says in the documentation: "...Currently it only supports permutation n of n objects", which is not what I want to do.

An almost trivial task at present, I have a group of 5 objects, from which I'm selecting 2 items at a time (5P2). I can do the calculation and work out there are 20 combinations but I'd like to implement an algorithm that builds the list of permutations, e.g. AB, AC, AD, AE, BA, BC, BD, etc. It's when the master set of objects gets to nearly 100 that manually building the 9900 permutations will become horrendous :)

If anyone can provide some clues, I'd appreciate it greatly.

John

In reply to Searching for a Permutation Algorithm for nPr where n != r by ozboomer

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