Re: Lists: Row Vectors vs. Column Vectors. (feels like such a silly

*To*: mathgroup at smc.vnet.net*Subject*: [mg110212] Re: Lists: Row Vectors vs. Column Vectors. (feels like such a silly*From*: Bill Rowe <readnews at sbcglobal.net>*Date*: Tue, 8 Jun 2010 07:08:53 -0400 (EDT)

On 6/7/10 at 8:08 AM, rgorka at gmail.com (telefunkenvf14) wrote: >Can someone explain why a list does not display in MatrixForm as a >row?---It's ok if the answer is computer sciency. I'll take some >advil before I attempt to digest any answers. :) Because a 1D list is not defined as either a row nor a column. An example of something that displays as a row in MatrixForm would be {Range[4]} Alternatively, something that displays as a column in MatrixForm is: List/@Range[4] But note: In[4]:= MatrixQ /@ {{Range[4]}, List /@ Range[4]} Out[4]= {True,True} That is, both of these constructs are seen as matrices by Mathematica and displayed appropriately by MatrixForm. Also, notice In[5]:= a = Range[4]; b = RandomInteger[1, {4, 4}]; In[8]:= b.a Out[8]= {3,1,8,7} In[9]:= a.b Out[9]= {10,5,3,7} showing it is up to you to determine whether a 1D list should be interpreted as a column vector or row vector.