Re: Scalars Instead of Lists with One Element
- To: mathgroup at smc.vnet.net
- Subject: [mg83526] Re: Scalars Instead of Lists with One Element
- From: Gregory Lypny <gregory.lypny at videotron.ca>
- Date: Thu, 22 Nov 2007 04:46:30 -0500 (EST)
- References: <fhu75c$72j$1@smc.vnet.net> <4742F294.5050606@gmail.com>
Thanks everyone for your insights, I've found the problem. Say you want to sum a list whose elements are 13 and 9. Mathematica will return a list with one element, {22}, rather than 22 if the original list is specified as a 2x1 column vector. x = {{13}, {9}}; y = Total@x >>> returns {22} This also happens if you write x as I have above, or you use Mathematica's Insert menu to create a more visually appealing column vector, but it does not happen if you define x as a 2x1 array using the Array command. I think it will happen with any matrix calculation whose result should otherwise be a scalar. If we now let y be the row vector {1, 1} then y.x >>> returns {22} The upshot of this is that any table that is created from calculations that make use of column vectors or matrix math will likely have a depth greater than 3, and you won't be able to cut and paste directly into a word processor or spreadsheet. I'm going to have a look at some of the work-arounds that have been suggested in this thread and my related thread "Copy and Pasting Tables into Spreadsheet". Gregory