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I know how to generate positive random numbers, but is it possible to
generate a random number in a range such [-9..+9] ?
tfyh

joss

On 2007-01-30 08:14:39 +0100, "Gerald Ebberink" <> said:

> Rand(1-9
>
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> -----Original Message-----
> From: Josselin [private.php?do=newpm&u=]
> Sent: dinsdag 30 januari 2007 8:10
> To: ruby-talk ML
> Subject: generating negative random numbers
>
> I know how to generate positive random numbers, but is it possible to
> generate a random number in a range such [-9..+9] ?
> tfyh
>
> joss

thanks ... I'd never think about it !

On Jan 29, 2007, at 11:10 PM, Josselin wrote:

> I know how to generate positive random numbers, but is it possible
> to generate a random number in a range such [-9..+9] ?

irb(main):001:0> def rrand(x)
irb(main):002:1> rand(2*x) - x
irb(main):003:1> end
=> nil
irb(main):004:0> rrand 9
=> -7
irb(main):005:0> rrand 9
=> -8
irb(main):006:0> rrand 9
=> 5
irb(main):007:0> rrand 9
=> -8

On 30/01/07, Josselin <> wrote:
> I know how to generate positive random numbers, but is it possible to
> generate a random number in a range such [-9..+9] ?
> tfyh
>
> joss
>
>
>

rand(19) - 9

Farrel

On 1/30/07, Josselin <> wrote:
> I know how to generate positive random numbers, but is it possible to
> generate a random number in a range such [-9..+9] ?
> tfyh

class Range
def rand
Kernel::rand(last - first + 1) + first
end
end

(-9..9).rand

martin

On 2007-01-30 08:05:18 +0100, Josselin <> said:

> I know how to generate positive random numbers, but is it possible to
> generate a random number in a range such [-9..+9] ?
> tfyh
>
> joss

thanks to all of u, got it, but why there is no 'standard' function in
the lib ...

On Jan 30, 2007, at 08:52 , Martin DeMello wrote:

> On 1/30/07, Josselin <> wrote:
>> I know how to generate positive random numbers, but is it possible to
>> generate a random number in a range such [-9..+9] ?
>> tfyh
>
> class Range
> def rand
> Kernel::rand(last - first + 1) + first
> end
> end
>
> (-9..9).rand

(-9...10).rand won't give the expected answer. I think the below
should fix the problem when the last entry in the range is excluded:

class Range
def rand
return first if exclude_end? && last == first
Kernel::rand(last - first + (exclude_end? ? 0 : 1)) + first
end
end