MATLAB Central Newsreader - choosing a number at random

choosing a number at random

Monica — Sun, 08 Nov 2009 01:45:04 -0500

I need Matlab to choose a number between 1 and 10 at random, but I'm not sure how to go about doing this.

Re: choosing a number at random

Nasser M. Abbasi — Sun, 08 Nov 2009 01:59:14 -0500

"Monica " <moh__krez@hotmail.com> wrote in message
news:hd57r0$8c2$1@fred.mathworks.com...
>I need Matlab to choose a number between 1 and 10 at random, but I'm not
>sure how to go about doing this.

If you want the random number to be drawn from uniform distribution, which I
assume that is what you want, then do

r = 10*rand

--Nasser

Re: choosing a number at random

Nasser M. Abbasi — Sun, 08 Nov 2009 02:04:14 -0500

"Nasser M. Abbasi" <nma@12000.org> wrote in message
news:VBpJm.18763$Wd1.2960@newsfe15.iad...
>
> "Monica " <moh__krez@hotmail.com> wrote in message
> news:hd57r0$8c2$1@fred.mathworks.com...
>>I need Matlab to choose a number between 1 and 10 at random, but I'm not
>>sure how to go about doing this.
>
> If you want the random number to be drawn from uniform distribution, which
> I assume that is what you want, then do
>
> r = 10*rand
>
>

opps, you wanted it from 1 to 10, then do

r = 1+9*rand

(see help on rand)

--Nasser

Re: choosing a number at random

ade77 — Sun, 08 Nov 2009 02:52:03 -0500

"Monica " <moh__krez@hotmail.com> wrote in message <hd57r0$8c2$1@fred.mathworks.com>...
> I need Matlab to choose a number between 1 and 10 at random, but I'm not sure how to go about doing this.

you might also try randi(max), generates random number from 1:max.

in your case randi(10)

Re: choosing a number at random

Peter Perkins — Wed, 11 Nov 2009 15:18:55 -0500

Nasser M. Abbasi wrote:

> opps, you wanted it from 1 to 10, then do
>
> r = 1+9*rand

Nasser, this is exactly the reason why we added RANDI a couple of releases ago: too easy to slip up.

Re: choosing a number at random

Greg Heath — Thu, 12 Nov 2009 00:22:02 -0500

On Nov 11, 10:18 am, Peter Perkins
<Peter.Perk...@MathRemoveThisWorks.com> wrote:
> Nasser M. Abbasi wrote:
> > opps, you wanted it from 1 to 10, then do
>
> > r = 1+9*rand
>
> Nasser, this is exactly the reason why we added RANDI a couple of releases ago: too easy to slip up.

Does rand ever generate 0 or 1?

Greg

Re: choosing a number at random

Nathan — Thu, 12 Nov 2009 00:30:18 -0500

On Nov 11, 4:22 pm, Greg Heath <he...@alumni.brown.edu> wrote:
> On Nov 11, 10:18 am, Peter Perkins
>
> <Peter.Perk...@MathRemoveThisWorks.com> wrote:
> > Nasser M. Abbasi wrote:
> > > opps, you wanted it from 1 to 10, then do
>
> > > r = 1+9*rand
>
> > Nasser, this is exactly the reason why we added RANDI a couple of releases ago: too easy to slip up.
>
> Does rand ever generate 0 or 1?
>
> Greg

From the documentation:
"r = rand(n) returns an n-by-n matrix containing pseudorandom values
drawn from the standard uniform distribution on the open interval
(0,1)."

Meaning, 0 < r < 1

-Nathan