Re: Applying rules to SparseArray

• To: mathgroup at smc.vnet.net
• Subject: [mg66430] Re: Applying rules to SparseArray
• Date: Fri, 12 May 2006 02:03:13 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

```On 5/11/06 at 2:13 AM, CGenie at gmail.com (CoolGenie) wrote:

>Let's say I've a matrix like this one: m=SparseArray[ {{1, 1} ->
>1, {1, 2} ->2, {3, 2} -> x}, {3, 3} ]; which looks like this in
>MatrixForm: 1 2 0 0 0 0 0 x 0 where 'x' is a variable coefficient.
>Is there any way to apply a rule {x->1} to this array? ( m/.{x->1}
>doesn't work )

This can be done as follows:

In[10]:=
m /. SparseArray[a_, b_, c_, d_] :> SparseArray[a, b, c,
d /. x -> 1]

Out[10]=
SparseArray[<\[InvisibleSpace]3\[InvisibleSpace]>,{3,3}]

In[11]:=
Normal@%

Out[11]=
{{1, 2, 0}, {0, 0, 0}, {0, 1, 0}}
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