Re^4: Primes. Again.


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Re^4: Primes. Again.

by Andrew_Levenson (Hermit)

on Apr 26, 2006 at 15:47 UTC ( [id://545813]=note: print w/replies, xml )

Need Help??

in reply to Re^3: Primes. Again.
in thread Primes. Again.

I, for the life of me, could not grasp the "length $_" concept (what it was testing for each entry), so we re-wrote it in a way that worked better for our comprehension.

use strict;
use warnings;
my @prime = (2); my $not_prime;
for my $i(3..100){
    $not_prime=0;
    for(@prime){
        next if int($i/$_)!=($i/$_);
        $not_prime=1;
    }
    push @prime, $i if $not_prime!=1;
}
print join "\n", @prime;
[download]

Thanks again for your help! (The next, last, and conditional-if's that you inadvertantly taught me are VERY welcomed pieces of information.)

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Re^5: Primes. Again.
by GrandFather (Saint) on Apr 26, 2006 at 21:06 UTC

length returns the length (number of characters) in a string. Because you were setting the string to empty I used length to test for that condition and skip the empty string.

Others have provided better solutions. I was more interested in keeping to the essential structure of your code and using that as a springboard for teaching a little Perl. I seem to have achieved that. :)

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