Re: For loops with mathematica....

• To: mathgroup at smc.vnet.net
• Subject: [mg101098] Re: [mg101069] For loops with mathematica....
• From: "David Annetts" <davidannetts at aapt.net.au>
• Date: Wed, 24 Jun 2009 06:30:57 -0400 (EDT)
• References: <200906231105.HAA08136@smc.vnet.net>

```Hi Julien,
>
> I am totally new to mathematica.
> I want to use a simple loop for but with many arguments in the loop...
> the help says to do
>
> Do[ thingstodo, {i,8}]
>
> i will go from 1 to 8 to do thingstodo.
>
> First question: what if I want i to go from 20 then 200 then
> 300 then 400, (can we give a sequence as argument?)

You can do this.  Try

Do[
PrintTemporary[ji],
{ji, {Range[20], Range[200, 300], 400}}
]

or
crange = Join[Range[20], Range[200, 300], {400}];
Do[
PrintTemporary[ji],
{ji, crange}
]

> Second question: I have a lot of line to do in things to do.
> should I separate everything with a ; (doesn t seem to work,
> or use a procedure or something?)

Multiple statements inside a loop have to be separated using ";".

As an example,
Do[
a = Sin[ji Degree];
b = Cos[ji Degree];
Print[ji, "\t", a, "\t", b],
{ji, 0, 90, 45}
]

As with any programming language, you'll want to put stuff in Module[]'s as