Re: Re: Searching for embedded zeros in list

*To*: mathgroup at smc.vnet.net*Subject*: [mg32158] Re: [mg32145] Re: [mg32136] Searching for embedded zeros in list*From*: Andrzej Kozlowski <andrzej at tuins.ac.jp>*Date*: Sun, 30 Dec 2001 02:54:23 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Something strange happened to this message in passage through the Internet and what I got back was not what I sent. The code for EmbeddedZeros should have been: In[1]:= EmbeddedZeros[l_List] := Module[{u = N[l]}, ReplaceList[u, {___, x_, v:(0...), y_, ___} :> RuleCondition[{x, v, y}, x != 0 && y != 0]]] Andrzej Kozlowski Toyama International University JAPAN http://platon.c.u-tokyo.ac.jp/andrzej/ On Sunday, December 30, 2001, at 08:00 AM, Andrzej Kozlowski wrote: > Since you do not let us know your "inelegant" code I can't be sure that > you will consider mine more elegant. > However, here it is: > > In[1]:= > EmbeddedZeros[l_List]:= > Module[{u=N[l]}, > ReplaceList[ > u,{___,x_,v:Repeated[0.0],y_,___}:> > RuleCondition[{x,v,y},x?â?0&&y?â?0]]] > > In[2]:= > a={0.75,0.,0,0.42,0.10,0.0,0.03}; > > In[3]:= > b={0.0,0.90,0.75,0.42,0.25,0.0}; > > In[4]:= > EmbeddedZeros[a] > > Out[4]= > {{0.75,0.,0.,0.42},{0.1,0.,0.03}} > > In[5]:= > EmbeddedZeros[b] > > Out[5]= > {} > > > On Saturday, December 29, 2001, at 02:46 PM, Coleman, Mark wrote: > >> Greetings, >> >> Can anyone suggest an efficient/elegant way of checking a list for >> 'embedded' zeros. By embedded I mean the occurence of one or more zeros >> between two non-zero elements (note: zeros at the ends of the list are >> not relevant). For instance, the following lists all contain embedded >> zeros: >> >> a={0.98,0.87,0.0,0.5,0.25} >> b={0.9,0.0,0.0,0.0,0.0,0.0,0.05} >> c={0.75,0.42,0.10,0.0,0.03} >> >> while this list does not d={0.0,0.90,0.75,0.42,0.25,0.0} >> >> By way of background, I am working on a problem involving estimating >> generators for Markov transition matrices. One condition that ensures >> that a generator *does not* exist is the presence of inaccessible >> states >> in any row of the matrix. Thus one need only find a single occurance of >> an inaccessible state to show that a generator does not exist. Hence >> the >> code need only locate one such state, not all of them. >> >> The Mathematica code I've written for this problem does work, but it is >> hardly >> "elegant". >> >> Any help would be much appreciated! >> >> Best regards, >> >> -Mark >> >> >> >> > > > >