Re^3: Grep Pattern

that's elegant...

$ ./1.grep_pattern.pl 
result is 1 2 5 6 9 10
$ cat 1.grep_pattern.pl 
#!/usr/bin/perl -w
use 5.011;

my @pat = ( 0, 1, 1, 0 );
my @result = grep { $pat[ $_ % @pat ] } 0..12;
say "result is @result";

__END__
$
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Re^4: Grep Pattern by LanX (Saint) on Dec 15, 2018 at 01:36 UTC
> that's elegant.. One should even be able to shorten it to (can't test right now) `grep { (0,1,1,0)[ $_ % 4 ] } 0..12;` But it's not as DRY, cause you need to change the 4 if you change the list. And of course it's not answering the OP s real question to filter any list. Cheers Rolf _{(addicted to the Perl Programming Language :) Wikisyntax for the Monastery FootballPerl is like chess, only without the dice}	[reply] [d/l]
Re^5: Grep Pattern by ikegami (Patriarch) on Dec 15, 2018 at 15:48 UTC
I was about to say it also creates a shitload of scalars, but it doesn't. `0,1,1,0` repeatedly places the same 4 scalars on the stack. They are created at compile-time and associated with the opcode that returns them. Not bad	[reply]