Re: Simply but handy question
- To: mathgroup at smc.vnet.net
- Subject: [mg124846] Re: Simply but handy question
- From: Barrie Stokes <Barrie.Stokes at newcastle.edu.au>
- Date: Thu, 9 Feb 2012 05:39:03 -0500 (EST)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <201202081029.FAA06451@smc.vnet.net>
Hi Paul
How about:
y = {{a, b}, {0, c}};
ClearAll[ somethingOrZero]
somethingOrZero[x_] := If[ SameQ[ x, 0 ], 0, 1 ]
Map[ somethingOrZero, y, {2} ].
Check the online Help for what the parameters of Map are, and what SameQ means.
Barrie
>>> On 08/02/2012 at 9:29 pm, in message <201202081029.FAA06451 at smc.vnet.net>,
jediwhelan <jediwhelan at googlemail.com> wrote:
> 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
- References:
- Simply but handy question
- From: jediwhelan <jediwhelan@googlemail.com>
- Simply but handy question