Re: Using a logical Or in the function definition
- To: mathgroup at smc.vnet.net
- Subject: [mg86693] Re: Using a logical Or in the function definition
- From: dh <dh at metrohm.ch>
- Date: Wed, 19 Mar 2008 05:20:53 -0500 (EST)
- References: <fro39q$i8a$1@smc.vnet.net>
Hi, Or (abrev: ||)is a logical operator, not the alternative pattern operator Alternatives (abrev: |). Therefore, what you want: ar[ r_Integer , Alternatives[s_Integer , s_Rational]] := r/s; hope this hepls, Daniel ahallam at iastate.edu wrote: > I would like to use Or in the function definition as in > > ab[ Or[r_Integer,r_Rational], Or[s_Integer,s_Rational] ]:=r/s; > > In other words, I want the function to take integers or ratios of > integers as arguments, but not real numbers which are not rational. > > But if I give the function integer arguments, it does not evaluate. > > If I try > > ar[ r_Integer , Or[s_Integer , s_Rational]] := r/s; > > and give an integer first argument it works and so on. >