Re: A simple swap function

*Subject*: [mg2165] Re: A simple swap function*From*: ianc (Ian Collier)*Date*: Wed, 11 Oct 1995 05:58:41 GMT*Approved*: usenet@wri.com*Distribution*: local*Newsgroups*: wri.mathgroup*Organization*: Wolfram Research, Inc.*Sender*: daemon at wri.com ( )

In article <44qj8g$s22 at ralph.vnet.net>, valentin at wam.umd.edu (William F. Campbell) wrote: > I think I must be missing something straightforward. I want a function > to swap the values of 2 lists. I defined ab={a,b}, and ba={b,a}, and > swap[v1_,v2_]:=Module[{temp=v1},v1=v2;v2=temp;], and I get an Iteration > limit exceeded error. When I look at ab, it looks like {Hold[a],Hold[b]} > (or maybe {Hold[b],Hold[a], I don't remember), and ba looks opposite. When > I tried to use the same function on numbers, it didn't work either. What's > wrong with what I'm doing, and how can I do what I want to do? Well, in this example you can simply use the Reverse function to swap your values: In[9]:= ab = {a,b} Out[9]= {a, b} In[10]:= ba = Reverse[ ab ] Out[10]= {b, a} I hope this helps. --Ian ----------------------------------------------------------- Ian Collier Technical Sales Support Wolfram Research, Inc. ----------------------------------------------------------- tel:(217)-398-0700 fax:(217)-398-0747 ianc at wri.com Wolfram Research Home Page: http://www.wri.com/ -----------------------------------------------------------