The trick is to make sure the call to param occurs in a list context:

my @cardnumbers = $q->param("17cardnumber");
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This is, by the way, documented in the POD for CGI.pm (perldoc CGI).

Books (and supporting authors who've contributed so much) are nice, but they don't update when the module updates =)

perl -e 'print "How sweet does a rose smell? "; chomp ($n = <STDIN>); 
+$rose = "smells sweet to degree $n"; *other_name = *rose; print "$oth
+er_name\n"'
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