Re: Pattern Syntax for Alternate Heads with Default Value
- To: mathgroup at smc.vnet.net
- Subject: [mg125874] Re: Pattern Syntax for Alternate Heads with Default Value
- From: Bill Rowe <readnews at sbcglobal.net>
- Date: Thu, 5 Apr 2012 05:55:29 -0400 (EDT)
- Delivered-to: firstname.lastname@example.org
On 4/4/12 at 4:27 AM, benp84 at gmail.com (Ben) 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 = 9 and f[1.5] = >2.25 and f = 6.25 In:= f[x_?(# \[Element] Reals &)] := x^2 f[x_] := 6.25 In:= Clear[y]; f[y] Out= 6.25 In:= f[.8] Out= 0.64 No need to test for integers since reals include integers.