Re: Re-evaluation of Conditional expressions
- To: mathgroup at smc.vnet.net
- Subject: [mg3485] Re: Re-evaluation of Conditional expressions
- From: Harald Berndt <haraldb at nature.berkeley.edu>
- Date: Sat, 16 Mar 1996 22:39:39 -0500
- Organization: University of California Forest Prodcts Lab
- Sender: owner-wri-mathgroup at wolfram.com
Patrice Quinton wrote: > > While teaching Mathematica, I found the following quite strange > behaviour of Conditional expressions in Mathematica. Define symbol y as follows: > > y = If[x,1,2] > ... > Is there a special reason for this? Any way to circumvent this problem? > -- Patrice: You have an answer for the "why" from David. To circumvent the problem, use SetDelayed[] rather than Set[], i.e., y := If[x,1,2] This will evaluate the If[] at the time you call y, using whatever value x has at that time. ______________________________________________________________________ Harald Berndt, University of California Research Specialist Forest Products Laboratory Phone: 510-215-4224 FAX: 510-215-4299 ==== [MESSAGE SEPARATOR] ====