Vyacheslav Karamov wrote:
>
> I've solved my problem with captures, but I don't understand how to get
> positions of matches:
>
> my $regex = qr
> {
> (?i) # Case-insensitive
> (
> [\x{2022}\*]* # Any number of bullet or asterisk characters
> [1-9]+ # One or more digits 1-9
> \s* # Any number of spaces
> (?:
> \-|\,|through|and # Zero or one dash, comma or "through" or "and"
> )*?
> \s* # Any number of spaces
> )+
> }msx;
>
> my $regex1 = qr
> {
> (?i) # Case-insensitive
> (
> (?:
> figure | fig[s]?[\.]?? | table | box | chapter | diagram | scheme |
> chart | plate | appendix | part | section | footnote | [p]{1,2}\.?? | page
> )
> \s* # Any number of spaces
> (?:
> [0-9]+ # One or more digits 1-9
> \s* # Any number of spaces
> (?:
> \-|\,|through|and|\s # Zero or one dash, comma or "through" or "and"
> )*
> \s* # Any number of spaces
> )+
> )
> }msx;
>
> my @vancouverCites =
> (
> "[4 5, Figure 3; 12 Chapter 4-5]",
> "[8, Chapter 10]",
> "[9 through 15, pp. 35-46]",
> "[11, pp. 35 Through 46]",
> "[see 1, 4]",
> "[e.g. 2, 5]",
> "[e.g. •2, ••5]",
> "[e.g. *2, **5]",
> "[for example 1,17]",
> "[2, 9]",
> );
>
> foreach my $c (@vancouverCites)
> {
> $c =~ s/$regex1//g;
> print "Text=\"$c\" ";
> my @matches = $c =~ /$regex/g;
> foreach my $arr (@matches)
> {
> print "Array = $arr " if defined $arr;
> }
> print " pos=$-[0] - $+[0]", "\n";
> }
>
>
> Output:
>
> Text="[4 5, ; 12 ]" Array = 5 Array = 12 pos=12 - 11
> Text="[8, ]" Array = 8 pos=5 - 2
> Text="[9 through 15, ]" Array = 9 Array = 15 pos=16 - 13
> Text="[11, ]" Array = 11 pos=6 - 3
> Text="[see 1, 4]" Array = 1 Array = 4 pos=10 - 9
> Text="[e.g. 2, 5]" Array = 2 Array = 5 pos=11 - 10
> Text="[e.g. •2, ••5]" Array = •2 Array = ••5 pos=14 - 13
> Text="[e.g. *2, **5]" Array = *2 Array = **5 pos=14 - 13
> Text="[for example 1,17]" Array = 1 Array = 17 pos=18 - 17
> Text="[2, 9]" Array = 2 Array = 9 pos=6 - 5
>
> Why $-[0] and $+[0] are *so strange*?
First of all, your code is very difficult to read without proper indendation.
With the luxury of the /x modifier on your regular expressions you can make
things much more legible, like this:
use charnames ':full';
my $regex = qr {
(
[\N{BULLET}\*]* # Any number of bullet or asterisk characters
[1-9]+ # One or more digits 1-9
\s* # Any number of spaces
(?:
\-|\,|through|and # Zero or one dash, comma or "through" or "and"
)*?
\s* # Any number of spaces
)+
}msxi;
And the same applies to your loops - they would be very much more readable if
you indented your code properly.
Now the reason for the odd values in @- and @+ are because of your line
my @matches = $c =~ /$regex/g;
which, because of the /g qualifier, matches the regular expression as many times
as possible. So by definition the last match attempt is a failure and the
contents of @- and @+ are no longer valid. If you write a loop like this
instead, which processes each match individually, you will see what you expect.
foreach my $citation (@vancouverCites) {
print qq(Text = "$citation"\n);
while ($citation =~ /$regex/g) {
print qq(pos = $-[0] to $+[0]\n);
}
print "\n";
}
I hope this helps,
Rob
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