Re: HoldForm
- To: mathgroup at smc.vnet.net
- Subject: [mg68117] Re: HoldForm
- From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
- Date: Mon, 24 Jul 2006 05:52:25 -0400 (EDT)
- Organization: The Open University, Milton Keynes, UK
- References: <e9v992$gjr$1@smc.vnet.net> <ea1n9d$pgf$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Jean-Marc Gulliet wrote: > Bruce Colletti wrote: >> Re Mathematica 5.2.0.0. >> >> This code displays the component differences of matrix subtraction (A-B): >> >> A = {{1, 2}, {3, 4}}; >> >> B = {{5, 6}, {7, -8}}; >> >> Map[MapThread[HoldForm[#1 - #2] &, {A[[#]], B[[#]]}] &, Range@2] >> >> As desired, the output is {{1 - 5, 2 - 6}, {3 - 7, 4--8}}. >> >> Two questions: >> >> - What's a better way to do this? >> >> - How can I replace the -- by +? >> >> Thankx. >> >> Bruce >> >> > A simpler approach that my preceding post is > > MapThread[TraditionalForm[HoldForm[#1] - #2] &, Flatten /@ {A, B}] > > that returns {1 - 5, 2 - 6, 3 - 7, 4 + 8}. Again, the above result is not a matrix. Sorry about these mistakes. To match exactly what you wanted, a component by component difference of two matrices, the expression should read MapThread[HoldForm[#1] - #2 & , {A, B}, 2] returns {{1 - 5, 2 - 6}, {3 - 7, 4 + 8}} as desired. Best regards, Jean-Marc