Re: Controlling function arguments

• To: mathgroup at smc.vnet.net
• Subject: [mg48818] Re: [mg48817] Controlling function arguments
• From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
• Date: Fri, 18 Jun 2004 02:12:41 -0400 (EDT)
• References: <200406170807.EAA27782@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```On 17 Jun 2004, at 17:07, Virgil Stokes wrote:

> I found the following Mathematica code:
>
>   NumberVectorQ[x_] := VectorQ[x] && And @@ NumberQ /@ x;
>   functionx[k_Integer?Positive, v_?NumberVectorQ, w_?NumberVectorQ,
> q_?NumberVectorQ] := .....
>
> where, I have left out the body of this function (functionx). What does
> the first line actually accomplish?
>
> --V. Stokes
>

The funny thing is that function defined in the first line NumerVectorQ
is not needed since Mathematica's built in function VectorQ takes a
second argument so that

VectorQ[{1,2,3},NumberQ]

True

NumberVectorQ[{1,2,3}]

True

In any case, the purpose of the function NumberVectorQ is to test that
the argument ssupplied to the fucntion are vectors of number. Actually,
it is probably better to use NumericQ rather than NumberQ since

NumberVectorQ[{1,2,Sin[2]}]

False

VectorQ[{1,2,Sin[2]},NumericQ]

True

Andrzej Kozlowski
Chiba, Japan
http://www.mimuw.edu.pl/~akoz/

```

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