Re: Changing names of variables in a loop
- To: mathgroup at smc.vnet.net
- Subject: [mg92199] Re: Changing names of variables in a loop
- From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
- Date: Tue, 23 Sep 2008 07:29:30 -0400 (EDT)
- Organization: The Open University, Milton Keynes, UK
- References: <gb7obt$ngj$1@smc.vnet.net>
kazik.lakomy at gmail.com wrote:
> do you know maybe is there a possibility to change a name of a
> variable in a loop? I'm not exactly sure how to explain it, so maybe
> instead of my words I paste a basic example that express my query:
>
> a1 = 1; a2 = 2; a3 = 3;
> func[g_] := g;
> Summ = 0;
>
> For[i = 1, i <= 3, i += 1,
> Summa += func[ai]]
>
> So something like this... I have tried to deal with this like with
> strings and have put func[a<>"i"] but it didn't work (quite logic).
> The general problem is much more complicated, this is only a part of
> it, so please do not suggest me how can I sum up three numbers, this I
> believe I know :) I would very appreciate any hints,
Use array/function notation: 'someName'['someNumber'] (w/o the quotation
marks). For instance,
In[1]:= a[1] = 1; a[2] = 2; a[3] = 3;
func[g_] := g;
Summ = 0;
For[i = 1, i <= 3, i += 1, Summ += func[a[i]]]
Summ
Sum[a[i], {i, 1, 3}]
Out[5]= 6
Out[6]= 6
Regards,
-- Jean-Marc