lib - generating a list of random number

[Josselin]

I try to generate an array of N random numbers in range between 2
integers min and max
but I don't understand very well how to coordinate the sue of srand and rand..
is there an already written function for that ? and btw is there any
place to find such useful functions ?

thanks

joss

 

[Robert Klemme]

I try to generate an array of N random numbers in range between 2
integers min and max
but I don't understand very well how to coordinate the sue of srand and
rand..

I am not sure I understand you here. What does "sue" mean here?

is there an already written function for that ? and btw is there any
place to find such useful functions ?

What about this?
=> [2, -4, -2, -1, -3, 1, 1, 1, -3, 0]

Kind regards

robert

 

[ara.t.howard]

I try to generate an array of N random numbers in range between 2 integers
min and max
but I don't understand very well how to coordinate the sue of srand and
rand..
is there an already written function for that ? and btw is there any place
to find such useful functions ?

thanks

joss

harp:~ > cat a.rb
n, max, min = 42, 10, 6
p Array.new(n).map{ rand((max - min) + 1) + min}


harp:~ > ruby a.rb
[6, 8, 8, 10, 9, 7, 6, 8, 9, 7, 10, 10, 7, 7, 9, 9, 6, 9, 10, 6, 8, 10, 6, 9, 7, 8, 8, 10, 8, 9, 9, 9, 10, 7, 9, 6, 6, 8, 8, 10, 9, 7]



-a

 

[Josselin]

I try to generate an array of N random numbers in range between 2
integers min and max
but I don't understand very well how to coordinate the sue of srand and rand..

I am not sure I understand you here. What does "sue" mean here?

is there an already written function for that ? and btw is there any
place to find such useful functions ?

What about this?
=> [2, -4, -2, -1, -3, 1, 1, 1, -3, 0]

Kind regards

robert

sorry sue => usage.... typing mistake...

thanks !!! that's exactly what I searched for...
I knew how to generate an array with an 'upper limit only' ...

 

[Josselin]

They are very easy to use, but first you have to decide what you want to do.
What do you want to do? What role does "srand()" play? Be specific.


For what, specifically? The range of random numbers, or the use of
"srand()"? If you always want the same sequence of random numbers, then
there is one solution, but if you always want a different sequence, there
is a different solution. Which do you want?


There sure is:

http://www.ruby-doc.org/ thanks

By the way, when you ask a question like this, it is best to express your
requirement as specifically as possible. You may have noticed that you got
two different replies to your inquiry, each with sample code that provided
differing interpretations of your request.

The solution to this problem is to leave no doubt about your requirement.
For example, when you say "between two integers" do you mean:

a < n < b

or
a <= n <= b

or some third possibility?

I apologize... I was looking for a result (how to generate a list of
random integer numbers between a minimum and a maximum .. included) ...
yes forgotten to specify including limits....

and at the same time trying to understand how to USE srand()and rand(),
my standard Ruby manual is clearly written but there is no example for
this function.
I googled a lot but without any success regarding examples...
my first thought was: srand() is useful in setting a limit to the
generator.... used by rand() so it could have been a clue to solve my
problem...

 

[khaines]

I googled a lot but without any success regarding examples...
my first thought was: srand() is useful in setting a limit to the
generator.... used by rand() so it could have been a clue to solve my
problem...

Use ruby-doc.org

http://ruby-doc.org/core/classes/Kernel.html#M002012


Kirk Haines

 

[Josselin]

srand refers to seed rand
rand is not generating a random number it is just picing a number from
a list of huge size srand says start from this position so passing in
the time.now before you start looping you will get more random results

thanks a lot ! got it ...