Matching degree-based geographical coordinates with a regular expression

Question

I\'d like to be able to identify patterns of the form

28°44\'30\"N., 33°12\'36\"E.

Here\'s what I have so far:

use utf8;
qr{
           


        

Answer 1

This:

use strict;
use warnings;
use utf8;
my $re = qr{
    (?:
    \d{1,3} \s*  °   \s*
    \d{1,2} \s*  '   \s*
    \d{1,2} \s*  "   \s*
    [ENSW]  \s* \.?
            \s*  ,?  \s*
    ){2}
}x;
if (q{28°44'30"N., 33°12'36"E.} =~ $re) {
    print "match\n";
} else {
    print "no match\n";
}

works:

$ ./coord.pl 
match

Answer 2

The ?: at the beginning of the regex makes it non-capturing, which is probably why the matches cannot be extracted or seen. Dropping it from the regex may be the solution.

If all of the coordinates are fixed-format, unpack may be a better way of obtaining the desired values.

my @twoCoordinates = unpack 'A2xA2xA2xAx3A2xA2xA2xA', "28°44'30"N., 33°12'36"E.";

print "@twoCoordinates";  # returns '28 44 30 N 33 12 36 E'

If not, then modify the regex:

my @twoCoordinates = "28°44'30"N., 33°12'36"E." =~ /\w+/g;

Answer 3

You forgot the x modifier on the qr operator.

Answer 4

Try dropping the use utf8 statement.

The degree symbol corresponds to character value 0xB0 in my current encoding (whatever that is, but it ain't UTF8). 0xB0 is a "continuation byte" in UTF8; it is expected to by the second, third, or fourth character of a sequence that begins with something between 0xC2 and 0xF4. Using that string with utf8 will give you an error.