Re: Function argument types
- To: mathgroup at smc.vnet.net
- Subject: [mg112954] Re: Function argument types
- From: Bill Rowe <readnews at sbcglobal.net>
- Date: Thu, 7 Oct 2010 03:38:09 -0400 (EDT)
On 10/6/10 at 3:16 AM, sam.takoy at yahoo.com (Sam Takoy) wrote: >I can't see to find the answer to this basic question: >What's the difference between >f[n_?Integer]:= This form allows n to be anything but tests to see if n is an integer. Execution of course happens only if the test returns true. >and >f[n_Integer]:= This form specifies n is an integer. No other n will match this pattern. So, the definition that follows will only be applied if n is an integer. From a practical standpoint, there really isn't much difference. The n_Integer form is a bit more specific and possibly a bit faster than n_?Integer. And since this is a bit easier to type n_Integer, this is the form I would use if I wanted to restrict f to integer values. >I would be happy to read more about this, but what's the keyword? The information on patterns can be found at tutorial/PatternsOverview