Re: Combinations
- To: mathgroup at smc.vnet.net
- Subject: [mg30779] Re: [mg30769] Combinations
- From: Andrzej Kozlowski <andrzej at tuins.ac.jp>
- Date: Wed, 19 Sep 2001 00:16:19 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
No, they are defintitely not present in the Mathematica Kernel. However, I think I am not the only one who is against the idea of littering the Kernel with such trivialities. I can't believe that you would fint it easier to write NumberOfPermutations[5] than 5! or NumberOfCombinations[7,5] than 7!/(5!2!). On Monday, September 10, 2001, at 09:43 AM, Dana wrote: > Hello. I have Mathematica 4.1 > > In a Program like Excel, or a hand-held calculator, one can return the > number of combinations and permutations. > > However, I can not find an equivalent function in Mathematica. > For example, Permutations[ ] returns a long list of all the "Actual" > permutations. > I am looking for just the final number. > If there is one, could you include 'how' you found it. I have looked > everywhere. > I know DiscreteMath`Combinatorica` has some stuff in it, but the Help > system > appears not to explain many of them. > > I can write a custom function, but I am curious to find out if this > function > is built in to Mathematica. > > I hope the answer is not to take the Length[ ] of a rather long list. > > TIA. Dana > > (I posted this question a month ago, but it never showed up in the > newsgroup, or in the archives. > I hope I am not doing something wrong.) > > > > > > Andrzej Kozlowski Toyama International University JAPAN http://platon.c.u-tokyo.ac.jp/andrzej/