Re: fill the empty spaces in a matrix

*To*: mathgroup at smc.vnet.net*Subject*: [mg46678] Re: [mg46625] fill the empty spaces in a matrix*From*: Tomas Garza <tgarza01 at prodigy.net.mx>*Date*: Fri, 27 Feb 2004 19:32:07 -0500 (EST)*References*: <35A9B2FA0511A74E9C5CDE284F052708042E72EF@tor-exm-03.wireless.corp.ads>*Sender*: owner-wri-mathgroup at wolfram.com

Ok, now I see. If you actually have empty spaces, but separated with a comma, then use ReplaceAll: In[1]:= aa = {{0, , 0}, {0, 0, 0}, {0, 0,}} Out[1]= {{0, Null, 0}, {0, 0, 0}, {0, 0, Null}} In[2]:= aa /. Null -> 0 Out[2]= {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}} If you have a symbol, say x (provided x has not been assigned a numerical value), then In[3]:= bb = {{0, x, 0}, {0, 0, 0}, {0, 0, x}} Out[3]= {{0, x, 0}, {0, 0, 0}, {0, 0, x}} In[4]:= bb /. x -> 0 Out[4]= {{0, 0, 0}, {0, 0, 0}, {0, 0, 0}} Tomas ----- Original Message ----- From: "Mike Bauer-TM" <Mike.Bauer at telus.com> To: mathgroup at smc.vnet.net Subject: [mg46678] RE: [mg46625] fill the empty spaces in a matrix Lets say aa is my matrix the spaces x marks the empty space. If I try to use this matrix in a calculation Mathematica will have a problem because the matrix in not even. Mathematica will see that the first row (0 x 0) does not have the same amount of elements as row 2 (0 0 0 ). Is there a way to tell Mathematica to automatically fill in the empty segments (x) with '0'. / 0 x 0 \ aa= | 0 0 0 | \ 0 0 x / or aa= {{0, ,0},{0,0,0},{0,0, }}; sorry for the misunderstanding. -----Original Message----- From: Tomas Garza [mailto:tgarza01 at prodigy.net.mx] To: mathgroup at smc.vnet.net Subject: [mg46678] Re: [mg46625] fill the empty spaces in a matrix I'm sorry about my ignorance, not knowing what you mean by an "uneven" matrix. In any case, you must specify which are the empty positions you want to fill. Tomas Garza Mexico City ----- Original Message ----- From: "Mike Bauer-TM" <Mike.Bauer at telus.com> To: mathgroup at smc.vnet.net Subject: [mg46678] [mg46625] fill the empty spaces in a matrix > > Hi all, > > I have an uneven matrix > / 0 0 \ > aa= | 0 0 0 | > \ 0 0 / > I want to fill the empty spaces with 0's, how do I do that. > > thank you > > > > >