Another way. Distinguishes undefined from non-existent keys (may be surplus to requirements). Needs 5.10+ for the // defined-or operator.
c:\@Work\Perl\monks>perl -wMstrict -le
"use 5.010;
;;
my @AoH = (
{ name => 'Adam', age => 0, },
{ name => 'Bob', age => 10, },
{ name => 'Cat', age => 20, },
{ name => '0', age => 30, },
{ name => 0, age => 35, },
{ name => '', age => 40, },
{ name => undef, age => 50, },
{ age => 60, },
);
;;
my @empty;
;;
print make_csv('name', @AoH);
print make_csv('name', @empty);
print make_csv('name');
print make_csv();
print make_csv('name', { name => 'Foo', age => 91, });
print make_csv('name', { name => '0', age => 92, });
print make_csv('name', { name => 0, age => 93, });
print make_csv('name', { name => '', age => 94, });
print make_csv('name', { name => undef, age => 95, });
print make_csv('name', { age => 96, });
;;
sub make_csv {
my $k = shift;
return
qq{'@{[ join q{','}, map exists $_->{$k} ? $_->{$k} // '[UNDEF]'
+: '???', @_ ]}'};
}
"
'Adam','Bob','Cat','0','0','','[UNDEF]','???'
''
''
''
'Foo'
'0'
'0'
''
'[UNDEF]'
'???'
Give a man a fish: <%-{-{-{-<