Re: Default and head in function argument
- To: mathgroup at smc.vnet.net
- Subject: [mg111623] Re: Default and head in function argument
- From: Leonid Shifrin <lshifr at gmail.com>
- Date: Sat, 7 Aug 2010 06:22:58 -0400 (EDT)
Hi, Clear[f]; f[x : (_Integer?Positive) : 3] := x^3 Regards, Leonid On Sat, Aug 7, 2010 at 9:31 AM, NP <nomplume69 at gmail.com> wrote: > Hi, > > I know how to define a function so that it evaluates only when the > head of the argument is of a certain type: > > Clear[f]; > f[x_Integer?Positive] := x^3 > f[3] > f[3.1] > f[-3] > > 27 > f[3.1] > f[-3] > > and I also know how to set default to an argument of a function like > so: > > Clear[f] > f[x_:3] > f[] > > 27 > > How do I do both i.e., specify head and default value? > > Thanks, > > NP > >