Greetings fellow monks,

A while back, I sought wisdom regarding a RegEx filter that would filter \s+ from a scalar but skip filtering between to marker labels. I got several really great replies, but I've wandered into a new problem: I need the same filter but allow for multiple marker labels. Here are the details:

I have an large string scalar and I'd like to filter out multiple white spaces, converting them into just a single space per instance. Here's an example of the scalar:

A Bridge Too Far     Hosted by Rod Stuart     Friendly Skys
42    STARTPRESERVE1 Life, the universe...   and Everything STOPPRESER
+VE1   Bob
HotWheels are cool     More movies on Fox           File server
A Bridge Too Far     Hosted by Rod Stuart     Friendly Skys
42    STARTPRESERVE2 Life, the universe...   and Everything STOPPRESER
+VE2   Bob
HotWheels are cool     More movies on Fox           File server

[download]

Sounds like a job for $text =~ s/\s+/ /g;, except that I want to avoid the filtering between multiple START and STOP markers. Here's the original code that uses a single pair of markers (provided by IO):

$text =~ s/\s+|(STARTPRESERVE.*?STOPPRESERVE)/${[$1,' ']}[!$1]/gs;

This works great exept that I now need multiple markers like STARTPRESERVE1 .. 3 and so forth. My first thought was a loop through an array of these markers doing a regex, but of course that won't work. So I think it needs to be a single regex. (Right?) So here's my feeble attempt: (Please try not to laugh.)

$$text_ref =~ s%
  (STARTPRESERVE1.*?STOPPRESERVE1)
|
  (STARTPRESERVE2.*?STOPPRESERVE2)
|
  (PRESERVESTART.*?PRESERVESTOP)
|
  \s+
%
  ((defined $1 and ($1 =~ /^\s+$/)) ? ' ' : $1) .
  ((defined $2 and ($2 =~ /^\s+$/)) ? ' ' : $2) .
  ((defined $3 and ($3 =~ /^\s+$/)) ? ' ' : $3)
%eigsx;

[download]

Am I headed in the right direction, or am I missing an easier solution? Thanks all.

gryphon
code('Perl') || die;

In reply to RegEx filter \s ! between labels, part 2 by gryphon

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