pattern matching an array

nkpgmartin has asked for the wisdom of the Perl Monks concerning the following question:

I'd like to do a for or foreach loop that grabs every line with matched array element and does something to that line. The array @reqs is not very big but has no consistent pattern and will change. Here is what I have so far:

for ($y=0; $y<@lines;$y+=1)
  {
  if (($lines[$y]=~/^\*R_/) && ($lines[$y]!~/BADSTRING/))
    {
    do something;
    }
  }
[download]

I'd like to add something like: && ($lines[$y]=~/@reqs/) ? but obviously this doesnt work . Thanks in advance.

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Re: pattern matching an array by broquaint (Abbot) on Jul 15, 2003 at 15:24 UTC
I'd like to add something like: `&& ($lines[$y]=~/@reqs/)` Then you can use a simple `grep` like so `if (($lines[$y]=~/^\*R_/) && ($lines[$y]!~/BADSTRING/) && grep $lines[$y] =~ $_, @reqs)` [download] This way if `$lines[$y]` matches any of the strings in `@reqs` that particular condition will return true. See. `grep` for more info. HTH `_________ broquaint`	[reply] [d/l]
Re: pattern matching an array by BrowserUk (Patriarch) on Jul 15, 2003 at 15:34 UTC
If `@reqs` contains simple string to match the complete line rather than regexes or partial matches, the you could create a hash and do a fast lookup. `%reqs; @reqs{ @reqs } = (); for( @lines ) { if( /^\*R/ && $_ !~ /BADSTRING/ && exists $reqs{ $_ } ) { # do something } }` [download] Lots of ifs, but much quicker when they are true. Examine what is said, not who speaks. "Efficiency is intelligent laziness." -David Dunham "When I'm working on a problem, I never think about beauty. I think only how to solve the problem. But when I have finished, if the solution is not beautiful, I know it is wrong." -Richard Buckminster Fuller	[reply] [d/l] [select]
Re: pattern matching an array by flounder99 (Friar) on Jul 15, 2003 at 19:33 UTC
If I understand you correctly @reqs is an array of "requirements" that if all are true you want to accept the line? If that is the case you can create a custom subroutine on the fly using eval `@reqs = qw/foo bar cat/; $reqsub = eval 'sub { ' . (join ' && ', map { '/\\Q' . $_ . '/'} @re +qs) . ' } '; while (<DATA>) { print if &$reqsub; } __DATA__ R_dog_cat_horse_foo_bar R_dog_cat_foo R_dog_cat_horse_bar R_dog_cat_horse_foo_bar R_cat_horse_foo_bar __OUTPUT__ R_dog_cat_horse_foo_bar R_dog_cat_horse_foo_bar R_cat_horse_foo_bar` [download] -- flounder	[reply] [d/l]