Re: Define function using lists or tables
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- Subject: [mg131427] Re: Define function using lists or tables
- From: "Nasser M. Abbasi" <nma at 12000.org>
- Date: Wed, 3 Jul 2013 22:04:42 -0400 (EDT)
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On 7/3/2013 3:49 AM, Joaquim Nogueira wrote:
> Hello. Possibly this is a very simple question.
>
> Is there a way to define a function over a (BIG) list of ordered pairs? I mean,
>suppose that I have a list, created using a Table command or something like that,
>of the form [{a,b},{c,d},etc.] such that, after naming it f, say,
>f = [{a,b},{c,d},etc.], then, afterwards, whenever there is a command such
>that one needs to compute f[a] (or f[c]), the program immediately replaces f[a] by b,and f[c] by d?
>
> Thank you.
>
This looks like a hash table. In Mathematica, it is build in. All what
you have to do is:
--------------
f[a] = b;
f[c] = d;
-------------
Now
---------------------
In[294]:= f[a]
Out[294]= b
--------------------
There are more advanced ways to do this for more complicated setups.
google the subject of hash tables with mathematica for more information.
--Nasser