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Re: Two questions related to Arrays

• To: mathgroup at smc.vnet.net
• Subject: [mg113327] Re: Two questions related to Arrays
• From: Sseziwa Mukasa <mukasa at jeol.com>
• Date: Sat, 23 Oct 2010 07:08:31 -0400 (EDT)

On Oct 22, 2010, at 1:35 AM, Sam Takoy wrote:

> Hi,
> 
> First, why doesn't the following return the first two elements of the 
> outer list:
> 
> 
> Cases[{{{1}, {2}}, {3, 4}, {{5}, 6}}, _Array]

Array is not a head, use ArrayQ yo find arrays.

Cases[{{{1}, {2}}, {3, 4}, {{5}, 6}}, _?ArrayQ]

> Second, I'm looking for help writing a function
> 
> f[t__]:=
> 
> that returns Outer[Times, u] where u only includes the input variables 
> that are Arrays.

Using the prior idea:

f[t__]:=Outer[Times,Sequence@@Cases[t,_?ArrayQ]]

Regards,
	Sseziwa