Re: grep { $var } @arr

Yes you can do that but I usually do it like this:

@res = grep (/$pat/g, @arr);

Perl 5.8.8 on Redhat Linux RHEL 5.5.56 (64-bit)

Comment on Re: grep { $var } @arr

Replies are listed 'Best First'.
Re^2: grep { $var } @arr by Laurent_R (Canon) on Jul 17, 2014 at 18:55 UTC
Well, bulrush, you did not say how you populate $pat, but I fail to see how a regex would figure out whether a value is larger or smaller than 3. I definitely agree that a subroutine reference is a very good solution, perhaps the best.	[reply]
Re^3: grep { $var } @arr by AppleFritter (Vicar) on Jul 21, 2014 at 09:54 UTC
I fail to see how a regex would figure out whether a value is larger or smaller than 3. You can get clever with match-time pattern interpolation. For instance: `my @list = (1..5); my $pattern = qr/\d+(??{if($& < 3) { "" } else { "(?<!\\d)" } })/; my @res = grep /$pattern/, @list; say join ", ", @res;` [download] This also (ab)uses negative look-behind assertions to create a subpattern that is guaranteed to fail (in this regex, not in general). But I agree, subroutine references are the way to go here.	[reply] [d/l]
Re^4: grep { $var } @arr by Laurent_R (Canon) on Jul 21, 2014 at 17:37 UTC
Yeah, that's clever ++, that that expression is far from being regular.	[reply]
Re^2: grep { $var } @arr by igelkott (Priest) on Jul 21, 2014 at 07:10 UTC
`/$pat/g` Perhaps I've misunderstood but with my current `$var`, using `/$pat/g` will result in no matches (with or without the 'g' modifier). As far as I know, this will look for the literal string of '$_ < 3' on my array, as written below (appending to the initial script). `@res = grep {/$pat/g} @arr; print "Search:\t@res\n";` [download] This finds none of the elements of `@arr`.	[reply] [d/l] [select]

In Section Seekers of Perl Wisdom