Re^2: Regular Expression Doubt

You seem to be arbitrarily splitting on spaces. This will break unless there's a clear space either side of the +. A better option would be as follows.

my $text = '1&plus;2<maths> &plus; dfdf</maths>';

my $output = "";
while ($text =~ m/((<maths>.*?<\/maths>)|([^<]*))/gs) {
    if ($2) {
        $output .= $2;
    } else {
        my $segment = $3;
        $segment =~ s/&plus;/&thinsp;&plus;&thinsp;/g;
        $output .= $segment;
    }
}
print $output . "\n";
[download]

The basic premise being to scoop up and ignore (push onto output) anything in <maths>, or scope up as much that can easily be determined not to be in <maths> (ie no angle brackets) and parse that before putting it on the output.

Comment on Re^2: Regular Expression Doubt Download Code

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Re^3: Regular Expression Doubt by Anonymous Monk on Apr 05, 2005 at 14:31 UTC
`my $text = '1 + 2 <br> <maths> + dfdf</maths>'; my $output = ""; while ($text =~ m/((<maths>.?<\/maths>)\|([^<]))/gs) { if ($2) { $output .= $2; } else { my $segment = $3; $segment =~ s/+/ + /g; $output .= $segment; } } print $output . "\n"; __END__ 1  +  2 br> <maths> + dfdf</maths>` [download] You lost a `<` here.	[reply] [d/l] [select]
Re^4: Regular Expression Doubt by reasonablekeith (Deacon) on Apr 05, 2005 at 15:09 UTC
dammit `my $output = ""; while ($text =~ m/((<maths>.*?<\/maths>)\|+\|.)/gs) { if ($2) { $output .= $1; } else { my $segment = $1; $segment =~ s/+/ + /g; $output .= $segment; } } print $output . "\n";` [download]	[reply] [d/l]
Re^5: Regular Expression Doubt by Anonymous Monk on Apr 06, 2005 at 08:41 UTC
Eh, if you go that way, it could be made much more efficient. No need for the s/// - you're matching any `+` already: `my $output = ""; while ($text =~ m{\G(?:+\|(<maths>.*?<\/maths>\|[^&<]+\|.))}gs) { $output .= $1 \|\| " + "; } print $output, "\n";` [download]	[reply] [d/l] [select]
Re^3: Regular Expression Doubt by sh1tn (Priest) on Apr 05, 2005 at 15:46 UTC
`# in rare cases with no spaces: ... $text =~ s/(?!\s)(<maths>)/ $1/g; ...` [download]	[reply] [d/l]