Re: Combinations function?

*To*: mathgroup at smc.vnet.net*Subject*: [mg5470] Re: [mg5447] Combinations function?*From*: Robert Pratt <rpratt at math.unc.edu>*Date*: Wed, 11 Dec 1996 03:15:54 -0500*Sender*: owner-wri-mathgroup at wolfram.com

Use the function KSubsets in the Combinatorica standard package. In[1]:= Needs["DiscreteMath`Combinatorica`"] In[2]:= ?KSubsets KSubsets[l,k] returns all subsets of set l containing exactly k elements, ordered lexicographically. In[2]:= KSubsets[{a,b,c,d},3] Out[2]= {{a, b, c}, {a, b, d}, {a, c, d}, {b, c, d}} Rob Pratt Department of Mathematics The University of North Carolina at Chapel Hill CB# 3250, 331 Phillips Hall Chapel Hill, NC 27599-3250 rpratt at math.unc.edu On Sat, 7 Dec 1996, Erik Kulstad wrote: > There is already a function to obtain the number of permutations possible > from a set (or list); but does anyone know of a function to obtain the > combinations? > > For example, if the set is {a,b,c,d}, I want to list all 3-member > combinations possible, yielding {{a,b,c},{a,b,d},{a,c,d},{b,c,d}}. > > > Thanks in advance, > Erik Kulstad > > > >