#!/usr/bin/perl -w

$_ = "The quick\n\nbrown fox\njumped.";

print "-------------\n";
foreach (/(.*)/gm){
  print "[$_]\n";
}

print "-------------\n";
foreach (split/\n/){
  print "[$_]\n";
}

print "-------------\n";
[download]

-------------
[The quick]
[]
[]
[brown fox]
[]
[jumped.]
[]
-------------
[The quick]
[]
[brown fox]
[jumped.]
-------------
[download]

Thanks Rhandom and davorg,

Looks like I had my problem the wrong way round - split is behaving as I originally thought it ought to - i.e. it *is* matching blank lines perfectly normally - but the regexp is producing more matches, as in the Quick Brown Fox above.

But I can't see (feeling particularly thick today) why the regexp produces those extra matches, even in the simple example above. Could someone elucidate?

Cheers,

andy.

It's probably a Death to Dot Star! issue. You should read that node and see if you can recast your regex to better define the data that you're trying to match. At the moment, it's matching "string\n\n" as three separate strings when you probably only want two.

--
<http://www.dave.org.uk>

"Perl makes the fun jobs fun
and the boring jobs bearable" - me

This is a little weird. Can somebody explain this.

#!/usr/bin/perl -w

$_ = "The quick\n\nbrown fox\njumped.";

print "-------------\n";
foreach (/(.*)$/gm){
  print "[$_]\n";
}

print "-------------\n";
foreach (/^(.*)/gm){
  print "[$_]\n";
}

print "-------------\n";
foreach (/^(.*)$/gm){
  print "[$_]\n";
}

print "-------------\n";
[download]

Produces the following

-------------
[The quick]
[]
[]
[brown fox]
[]
[jumped.]
[]
-------------
[The quick]
[]
[brown fox]
[jumped.]
-------------
[The quick]
[]
[brown fox]
[jumped.]
-------------
[download]

Even though I found a solution to the problem, I still don't have an explanation for it. Does anybody know what is going on in the engine?

I've added use re qw(debug); to the script and looked and in the first example it says it matched 0 of 32767 times when the position is still on character 9. On the second set, this doesn't happen. How is this matching twice on the first time. Also I tried this

#!/usr/bin/perl -w

$_ = "The quick\n\nbrown fox\njumped.";

print "-------------\n";
foreach (/(?:^|\G)(.*)/gm){
  print "[$_]\n";
}

print "-------------\n";
[download]

And look what it did

-------------
[The quick]
[]
[]
[brown fox]
[]
[jumped.]
[]
-------------
[download]

Hmmmmmmm.

Can you post some code. I don't think I understand what you're saying. I tried the following:

#!/usr/bin/perl -w
use strict;

$_ = 'This is
a string

with
newlines

and

blank lines';

my @arr = split /\n/;

print map { "|$_|\n" } @arr;
[download]

a nd it gave this output:

|This is|
|a string|
||
|with|
|newlines|
||
|and|
||
|blank lines|
[download]

which looks right to me. What were you hoping for?

"Perl makes the fun jobs fun
and the boring jobs bearable" - me

Update: I just tried this code, and it works as I expect.

$_ = "one
two
three

four


";
foreach my $line (split(/\n/)) {
    print "$line\n";
}
[download]

$ perl ~/split.pl
one
two
three

four

No, they're scattered randomly through the string. But thanks for the idea, TheoPetersen. I've looked at perlfunc:split again - still no joy.

Slight modification - I've realised I don't need the /m on the regexp. Works the same without.

andy.

update: thanks again. I've realised that I was being stupid - the onset of tunnel vision. split was doing exaclty what it ought, as your example shows, but the regexp was returning extra blank lines.