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Re: More /.{I->-1} craziness

• To: mathgroup at smc.vnet.net
• Subject: [mg106191] Re: More /.{I->-1} craziness
• From: David Bailey <dave at removedbailey.co.uk>
• Date: Mon, 4 Jan 2010 06:01:43 -0500 (EST)
• References: <hhf5s3$h4o$1@smc.vnet.net> <200912310816.DAA24818@smc.vnet.net> <hhkj5p$534$1@smc.vnet.net> <201001021009.FAA07672@smc.vnet.net> <hhpl5k$9ng$1@smc.vnet.net>

Murray Eisenberg wrote:
> David,
> 
> Wow: you covered quite a bit that first day!
> 
> Happy New Year,
> Murray
> 
> David Bailey wrote:
>> ... when I gave introductory 
>> Mathematica courses, I covered the pitfalls of replacement rules on day one!
> 
Well I like ReplaceAll to substitute variables in expressions, rather 
than starting with assignments like

x=42

People invariably forget they have made top-level assigments to 
variables like that, and get into difficulties a few minutes later. Of 
course, that led into a discussion of what you could and couldn't do 
with ReplaceAll.

If you start them  with assignments, many students do everything with them!

David Bailey
http://www.dbaileyconsultancy.co.uk

• References:
  • Re: More /.{I->-1} craziness
    • From: David Bailey <dave@removedbailey.co.uk>