Re: random number

[insensate]

Here's a snippit that will initialize an array and select a number while the array still has elements...what you do with the element is up to you...

use strict;
my $max = 200;                                #number of elements for 
+array
my @array = (0..$max-1);                      #initialize array
while(@array !=0){
  my $index   = rand @array;                  #pick a random element o
+f the existing array
  my $element = $array[$index];               #extract the element
  my @newarray = grep {$_ !=$element} @array; #remove the element
  @array = @newarray;                         #reset the array
}

Addendum: See BrowserUk's reply for a more tidy/efficient method of extracting the element from the array

[BrowserUk]

Given that you know the index of the item you want to remove from the array, it would be much more efficient to use splice instead of grep to remove the item from the array.

#replace
 my @newarray = grep {$_ !=$element} @array; #remove the element
#with
  splice @array, $index, 1; #remove item from array;
# and remove this. No need as the array has been modified.
# @array = @newarray;             #reset the array

---

Examine what is said, not who speaks.

[I0]

#splice is still O(n)
$array[$index] = $array[-1];
pop @array;

[BrowserUk]

True. And that's a neat solution.

It would still be better to shuffle the array and simply pop the next one when you need it as was suggested at near the top of the thread.

---

Examine what is said, not who speaks.

[sauoq]

Shuffling the array as suggested by BrowserUk and traveler is the Right Way To Do It™ but if you insist on removing elements from the array, how about

perl -le '@a=1..200; print while $_ = splice @a, rand @a, 1'

?

-sauoq
"My two cents aren't worth a dime.";

[huskey]

thank you. it worked perfect.