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Re: Pattern Syntax for Alternate Heads with Default Value

• To: mathgroup at smc.vnet.net
• Subject: [mg125863] Re: Pattern Syntax for Alternate Heads with Default Value
• From: Murta <rodrigomurtax at gmail.com>
• Date: Thu, 5 Apr 2012 05:51:39 -0400 (EDT)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com
• References: <jlh0n6$t6m$1@smc.vnet.net>

On Apr 4, 5:28 am, Ben <ben... at gmail.com> wrote:
> I'm trying to build a unary function which accepts only arguments with
> two possible heads and has a default value.  That is, something like
> the following, except that this doesn't work.  Anyone know how to do
> this correctly?
>
> f[(x_Real | x_Integer) : 2.5] := x^2;
> where f[3] = 9
> and f[1.5] = 2.25
> and f[] = 6.25

Hi Ben
Maybe something like that?

f[x_ (Real | Integer)] := x^2; f[] = 6.25;

(But all Integer are Real, I don't understand the application.
It could be f[x_Real: 2.5] := x^2)
best regards
Murta