Re: Lists and rules

*To*: mathgroup at smc.vnet.net*Subject*: [mg66510] Re: Lists and rules*From*: Bill Rowe <readnewsciv at earthlink.net>*Date*: Wed, 17 May 2006 03:30:18 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

On 5/15/06 at 11:49 PM, thomas.??? at balliol.ox.ac.uk (Thomas Schmelzer) wrote: >Experts, I would like to produce a decent piece of code for one of >my projects. I am constructing a list of sets >S_1, S_2 and S_3 >where S_j = { m , T[[1,m]] == j, m running from 1 to 100} >T[[1,*]] is a row vector containing only 1, 2 and 3. >I could setup a for loop and work with append. I have done that, but >I believe this approach is neither efficient nor elegant. Any hints >for a newbie? Table will do what you want. That is Table[{m, T[[1,m]]==j},{j,3},{m,100}] will return a list containing all three lists. Note, I have assumed when you wrote T[[1,m]]==j you have correctly shown what you want to do. If T[[1,j]] actually does return a row vector then T[[1,m]]==j will always be False since j is an integer. In this case the code I wrote will return exactly the same as: Table[{m,False},{j,3},{m,100}] which doesn't seem very useful. -- To reply via email subtract one hundred and four