Manipulating Arrays

webchalkboard has asked for the wisdom of the Perl Monks concerning the following question:

Hi again,

I have a much simplier and cooler question this time, and was wondering the best way to do this.

Basically I have an array of words for example ('the','cat','sat','on','the','matt') and I want to create lots of different combinations of these words, so I would like to end up with short two word phrases like 'cat matt' and 'cat sat' or 'matt cat the'.

What is the best way of achieving this result? I was thinking about counting the number of items in the array and then connecting random elements together. Most phrases would only be about 4 words long, and if I could get every permutation of these words up to say 50 permutations that would be perfect... i'm sure there is a cool perl way, any suggestions?

Many thanks,
Tom

Learning without thought is labor lost; thought without learning is perilous. - Confucius

WebChalkboard.com | For the love of art...

Comment on Manipulating Arrays

Replies are listed 'Best First'.
Re: Manipulating Arrays by Taulmarill (Deacon) on Aug 11, 2005 at 11:57 UTC
you should have a look at the Algorythm::Permute module on CPAN.	[reply]
Re^2: Manipulating Arrays by holli (Abbot) on Aug 11, 2005 at 12:04 UTC
Algorithm::Permute, that is. holli, /regexed monk/	[reply] [d/l]
Re: Manipulating Arrays by davidrw (Prior) on Aug 11, 2005 at 12:28 UTC
Besides the above, also take a look at this Q&A entry for other code: Categorized Questions and Answers QandASection: arrays How do I find all possible combinations of a list?	[reply]
Re: Manipulating Arrays by Limbic~Region (Chancellor) on Aug 11, 2005 at 12:37 UTC
webchalkboard, Ok, you speak of combinations and of permutations. They are not the same thing. In a nutshell, a combination doesn't ~~not~~ consider a group of elements different if the only thing that changes is the position while a permutation does. So do you want combinations or permutations? Additionally, it looks like you want both a fixed size (you mention 2 word phrases and then 4 word long phrases) and a fixed total (50). Do you have unspoken requirements - if so what are they. I have code (and so do other monks and CPAN) that does combinations, permutations, fixed size groupings, etc. I need more information before I can recommend one of them. Cheers - L~R Update: I did have a double negative pointed out by AM below. The correction is to strike one of them as order doesn't matter in combinations. The attempted correction by AM is incorrect.	[reply]
Re^2: Manipulating Arrays by Anonymous Monk on Aug 11, 2005 at 15:45 UTC
a combination doesn't not consider a group of elements different if the only thing that changes is the position while a permutation does Confusion alert! Confusion alert! That sentence is extremely hard to understand, even though I know what you're trying to say. I think one of the most egregious problems is the double negative, doesn't not. For the sake of others, I'll try to translate: The ordering of the elements matters for a combination, but doesn't matter for a permutation.	[reply]
Re: Manipulating Arrays by chester (Hermit) on Aug 11, 2005 at 13:18 UTC
I posted Re: Subphrases from a phrase in answer to another node, and it wasn't a good answer for that node, but it kind of is for this one. : ) But yeah, Math::Combinatorics looks like it might be another option for you.	[reply]
Re: Manipulating Arrays by salva (Canon) on Aug 11, 2005 at 12:50 UTC
it looks like a task for AI::Prolog...	[reply]
Re: Manipulating Arrays by webchalkboard (Scribe) on Aug 11, 2005 at 13:11 UTC
Thanks for all the hints, enough to keep me going for a while i'm sure :) Learning without thought is labor lost; thought without learning is perilous. - Confucius WebChalkboard.com \| For the love of art...	[reply]


Welcome to the Monastery
	PerlMonks