Re: For Loop and Array related
- To: mathgroup at smc.vnet.net
- Subject: [mg58032] Re: [mg57971] For Loop and Array related
- From: "Koffijberg, H." <H.Koffijberg at umcutrecht.nl>
- Date: Thu, 16 Jun 2005 05:38:07 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
While I've no idea exactly why your code fails (although i = 16000
should be i <= 16000, but that's not the problem) I found that
assigning the random integer value to a variable solves this
problem. Using the code:
Lattice = Table[0, {n, 100}];
For[i = 1, i <= 16000, i++, r = Random[Integer, {1, 100}]; Lattice[[r]]++];
Total[Lattice] always returns exactly 16000. I've programmed in C++ a lot
but I guess this is not a Mathematica syntax problem but some internal
Mathematica issue. Anybody else knows what's going on here ?
Best regards,
Erik Koffijberg.
-----Original Message-----
From: mchangun at gmail.com [mailto:mchangun at gmail.com]
To: mathgroup at smc.vnet.net
Subject: [mg58032] [mg57971] For Loop and Array related
Hi All,
I have an array with 100 elements, all set to zero initially. Then I
want to randomly choose one element and increase its value by one, and
repeat this 16000 times. Here is my code:
Lattice = Table[0, {n, 100}];
For[i = 1, i = 16000, i++, Lattice[[Random[Integer, {1, 100}]]]++]
So now if I add all the elements in the list Lattice together, I should
get 16000 (I use Total[Lattice] to get the sum of the list). But this
doesn't happen, and strangely, each time I run this, the sum of the
list is different! What am I doing wrong?
Also I'm aware that a lot of Mathematica newbies try and write code
like it were C++ and I think i've fallen into this trap as well. So is
there a different (more Mathematica) way which I can implement the
above?
Thanks in advanced.