Not a Sieve

Replies are listed 'Best First'.

Re: The Sieve
by Athanasius (Archbishop) on Mar 16, 2015 at 14:16 UTC

Nice! I like the way you’ve used the x operator. By removing the subroutine I was able to golf it down to this:

for($i=2;@p<50;++$i){$x=!!($i%$_)or goto _ for@p;push@p,$i;_:print"$i,
+"x$x}
[download]

16 characters saved, plus a C-style for loop and a goto! Bwahaha!

by Schmunzie (Beadle) on Mar 17, 2015 at 03:49 UTC

Love it! I didn't know that goto existed in Perl. Oh what fun to be had. Now all we need is ALTER from COBOL (anyone remember that?)

by Schmunzie (Beadle) on Mar 17, 2015 at 17:01 UTC

Oops, at the risk of being picky, your solution doesn't print 2.

by Athanasius (Archbishop) on Mar 18, 2015 at 02:19 UTC

D’oh! Don’t know how I missed that. This one (77 characters) does print 2:

for($i=2;@p<50;++$i){($x=!($i%$_))&&goto _ for@p;push@p,$i;_:print"$i,
+"x!$x}
[download]

Cheers,

Also not a sieve
by ambrus (Abbot) on Mar 16, 2015 at 15:55 UTC

print"$_,"x(1x$_)!~/^(11+)\1+$/ for 2..232
[download]

by hdb (Monsignor) on Mar 16, 2015 at 17:56 UTC

Which is not a Sieve! But then the OP's proposal is neither...

Update: this is a sieve (specify sieve size on command line):

$_=";"x(pop);s;.;.;;$;=~s:.:.:g,s:($;).:$1.:g,s,($;).,$1:,while($;)=m:
+(.+?);:;s;:;1+pos();ge;say
[download]