Re: Building clusters out of a nested list

*To*: mathgroup at smc.vnet.net*Subject*: [mg114982] Re: Building clusters out of a nested list*From*: Vince Virgilio <blueschi at gmail.com>*Date*: Sun, 26 Dec 2010 04:01:38 -0500 (EST)*Reply-to*: comp.soft-sys.math.mathematica at googlegroups.com

On Thursday, December 23, 2010 3:56:51 AM UTC-5, Dmitry wrote: SNIP > suppose I have a list of the form { {A,B,C},{C,D},{E,F},{F,H}}. I need > to build a list whose entries are unions of all entries of the > original list with nonzero intersection. For the example above, the > end result is {{A,B,C,D},{E,F,H}}. SNIP This works for your case and a few others. And it might scale better than other solutions, since I think it uses the pattern matcher less. l = {{a, b, c}, {c, d}, {e, f}, {f, h}}; Outer[UnsameQ@## && Intersection@## =!= {} && Union@## &, l, l, 1] // DeleteDuplicates@Level[#, {-2}] & {{a, b, c, d}, {e, f, h}} Vince Virgilio