Re: Simply but handy question
- To: mathgroup at smc.vnet.net
- Subject: [mg124857] Re: Simply but handy question
- From: Alexei Boulbitch <Alexei.Boulbitch at iee.lu>
- Date: Thu, 9 Feb 2012 05:42:53 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
Dear group members,
I am new to mathematica (well, I'm not actually but I haven't used it
in 5 years +).
Is there an easy way to return a matrix X of 1's and 0's to test
whether the entries in Y
are different from zero.
i.e.,
if Y = {{a,b},{0,c}}
Then X would return
X = {{1,1},{0,1}}
This would be handy for very large or complicated matrices where one
would like to know if specific entries are zero?
Many thanks,
Paul
Hi, Paul,
Try this:
matrix1 = {{a, b}, {0, c}};
matrix2 = {{a, b, 0}, {c, 0, 15}, {0, 2, d}};
g[a_] := If[a =!= 0, 1, 0];
Map[g, matrix1, {2}] // MatrixForm
Map[g, matrix2, {2}] // MatrixForm
Have fun, Alexei
Alexei BOULBITCH, Dr., habil.
IEE S.A.
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e-mail: alexei.boulbitch at iee.lu<mailto:alexei.boulbitch at iee.lu>