Re: Re: Re: Another question on lists

*To*: mathgroup at smc.vnet.net*Subject*: [mg80731] Re: [mg80711] Re: [mg80641] Re: [mg80618] Another question on lists*From*: Carl Woll <carlw at wolfram.com>*Date*: Thu, 30 Aug 2007 02:36:31 -0400 (EDT)*References*: <27088617.1188205442155.JavaMail.root@m35> <200708280603.CAA14009@smc.vnet.net> <11155728.1188404471045.JavaMail.root@m35> <op.txt02ysvqu6oor@monster.gateway.2wire.net>

DrMajorBob wrote: > So the simplest method is > > Last@Sort@sample Except that Sort[sample] is an O(n log n) operation, and Ordering[sample, -1] is an O(n) operation. Carl > > Bobby > > On Wed, 29 Aug 2007 03:24:08 -0500, Carl Woll <carlw at wolfram.com> wrote: > >> DrMajorBob wrote: >> >>> Here's an example: >>> >>> sample = Array[ >>> RandomInteger[{1, 10}, {RandomInteger[{3, 10}]}] &, {15}] >>> Length /@ % >>> >>> {{5, 7, 7, 1, 2, 5, 2, 7, 3}, {3, 4, 3, 8, 8}, {1, 4, 6, 6, 1, 6, >>> 3}, {4, 6, 1, 9, 9, 7, 3, 5, 10}, {9, 1, 4, 2, 7, 1, 5}, {2, 8, 2, >>> 4, 7, 3, 8}, {2, 10, 4, 7, 2, 10, 3}, {10, 5, 10, 6, 5, 10, 4, 3, >>> 4}, {5, 2, 3, 10, 8}, {5, 1, 7}, {1, 5, 8, 4, 8, 5, 8, 2}, {3, 3, 8, >>> 5, 1, 7}, {6, 10, 1, 6, 3, 5, 7, 6, 1, 7}, {3, 5, 1, 6, 6}, {10, >>> 10, 9, 3, 9}} >>> >>> {9, 5, 7, 9, 7, 7, 7, 9, 5, 3, 8, 6, 10, 5, 5} >>> >>> Last@SortBy[sample, Length] >>> >>> {6, 10, 1, 6, 3, 5, 7, 6, 1, 7} >>> >>> or >>> >>> sample[[Ordering[sample, -1, Length[#1] < Length[#2] &]]] >>> >>> {{6, 10, 1, 6, 3, 5, 7, 6, 1, 7}} >>> >>> >> Just a minor comment that the third argument of Ordering is not needed >> in this case, since the default order used sorts by length of list >> first. Try: >> >> sample[[Ordering[sample,-1]]] >> >> instead. >> >> Carl Woll >> Wolfram Research >> >>> Bobby >>> >>> On Sun, 26 Aug 2007 22:20:22 -0500, Mauricio Esteban Cuak >>> <cuak2000 at gmail.com> wrote: >>> >>> >>> >>>> Hello again.Thank you very much for your previous help. However, I >>>> seem to stumble on another rock: >>>> >>>> I have a list of n sub-lists with different number of elements. I >>>> want to select the list with the highest number of elements. >>>> I tried to combine the Select function with Lenght but couldn't do it: >>>> >>>> Select[list, Length /@ list >= Max[Length /@ list] &] >>>> >>>> Thanks for reading. >>>> >>>> Regards, >>>> >>>> cd >>>> >>>> P.D.: Any tips,websites, books, on how to learn some basic programming >>>> on Mathematica? >>>> I'm slowly beginning to read "The Mathematica Book"...should I just >>>> concentrate on that? >>>> >>>> >>>> >>>> >>> >>> >>> >>> >>> >> >> >> > > >

**References**:**Re: Another question on lists***From:*DrMajorBob <drmajorbob@bigfoot.com>