in reply to Am I doing Greedy Matching?

As far as i can see, yes you are greedy-matching.

Before i start: You don't seem to use strict; and use warnings;, neither the 3-argument version of open, nor checking if open actually worked. Filehandles should also be written as scalars ("$hello") - which you would have noticed when using strict.

I'm a bit oldstyle, i would do it like this:

my @sourceDBHostsFromTnsEntry;
my @sourceDBPortsFromTnsEntry;
open(my $SOURCETNS, "<", "/home/$User/Work/PROJ/$sourceTnsFileName") o
+r die($!);
while((my $record = <$SOURCETNS>)) {
    chomp ($record);
    my @parts = split /\ /, $record;
    foreach my $part (@parts) {
        if($part =~ /HOST=(.*)/o) {
            push @sourceDBHostsFromTnsEntry, $1;
        }
        if($part =~ /PORT=(.*)/o) {
            push @sourceDBPortsFromTnsEntry, $1;
        }
    }
}
close($SOURCETNS);

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If i wrote the program, i also would have decided to use shorter variable names (e.g. names that could be keyed in by remembering them instead of having to do copy&paste ;-)

I didn't test this specific code and there are probably "nicer" ways to do it but it should get the job done (although there may be the odd typo).

Explanation: In the first step, i read in a line and chop it up on the "space" delimeter into @parts. Then, foreach $part in @parts i match against the two tags "HOST=" and "PORT=". If it matches, i put the remainder into their respective arrays.

Don't use '#ff0000':
use Acme::AutoColor; my $redcolor = RED();
All colors subject to change without notice.

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Re^2: Am I doing Greedy Matching?
by jwkrahn (Abbot) on Nov 10, 2011 at 12:06 UTC
    In the first step, i read in a line and chop it up on the "space" delimeter into @parts.

    You also chomp the line which isn't required because (.*) will not match a newline.

    And you are using the /o option which is superfluous because there are no variables in the pattern to interpolate.

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      You also chomp the line which isn't required

      Quite right, it isn't required (and could hurt performance slightly on a big file). Over time, it has become part of my coding style to always use chomp when reading from a filehandle. More than once did i change the regex or some other part of the code and suddenly wondered where the newline came from. So i started using chomp unless required otherwise.

      And you are using the /o option which is superfluous because there are no variables in the pattern to interpolate.

      Again you are quite right. Does this actually hurt performance? I find it rather helpful when coding, even in static expressions, since i could just glance at the end and see "ok, this isn't a dynamic regex" instead of looking through the whole line noise for variables.

      But thats probably just me. You know, old dogs, new tricks...

      Don't use '#ff0000':
      use Acme::AutoColor; my $redcolor = RED();
      All colors subject to change without notice.
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