[Date Index] [Thread Index] [Author Index]

Re: Automatic update of variables

• To: mathgroup at smc.vnet.net
• Subject: [mg110335] Re: Automatic update of variables
• From: Bill Rowe <readnews at sbcglobal.net>
• Date: Sun, 13 Jun 2010 04:13:30 -0400 (EDT)

On 6/12/10 at 5:31 AM, adejuarez at gmail.com (Antonio De Ju=C3=A1rez) wrote:

>Sometimes, I would find useful a method to update variables
>automatically. For example, given the delayed rule

>b:=3 a+1;

>it would be useful to have b updated whenever a is assigned a new
>value, like a=37. Is there any method to do this in Mathematica?

Given:

In[11]:= b := 3 a + 1

In[12]:= a = 3; b

Out[12]= 10

In[13]:= a = 30; b

Out[13]= 91

It seems SetDelayed is doing precisely what you are requesting.