selecting within elements of arrays

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

Hi, i have an element of an array which looks something like this;

/:swiss|Q9L572|DNAA_STRPY
/:tremblnew|AAK98805|AAK98805
/:swiss|O08397|DNAA_STRPN
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etc in a long list. i am trying to write a script that extracts all hits beggining with /:swiss. My attempted if statement is below, it doesn't get any error messages but it also doesn't run! can anyone help??


if ($array[1] eq /^\/:swiss| (\d+)|(\d+)/)
{
print $array[1];
}
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Re: selecting within elements of arrays by broquaint (Abbot) on Jun 05, 2002 at 10:30 UTC
The problem is that you're not escaping the meta-character pipe(`\|`) which alternates sequences in regex (see. `perlre` for more info on regexes). Also you're using the string comparision operator and not the regex matching operator `=~` (see. `perlop` for more info on operators in perl) to match on `$array[1]`. To get your example to work you could do something like this `if($array[1] =~ m{ /:swiss \\| \w+ \\| \w+ }x) { ... }` [download] And if you wanted to do this match on an array of strings you could do something like this `my $match_re = qr{ ^ /:swiss \\| \w+ \\| \w+ }x; foreach my $line (@array_of_strings) { if($line =~ /$match_re/) { ... } }` [download] HTH `_________ broquaint`	[reply] [d/l] [select]
Re: selecting within elements of arrays by Joost (Canon) on Jun 05, 2002 at 10:35 UTC
Your match doesn't work because you have whitespace in your regex, and you don't use the /x modifier, and you don't escape the '\|' - oh and you cannot match a regex with 'eq' - you need '=~' (or match the $_ var) . You might also try simplifying the match: `foreach (@array) { # means foreach $_ (@array) { next unless /^\/:swiss\\|/; # means next unless $_ =~ /^\/:swiss\\|/; print; # means print $_; }` [download] `-- Joost downtime n. The period during which a system is error-free and immune from user input.` [download]	[reply] [d/l] [select]