Thank you for your suggestion. Unfortunately it does not solve the problem. I do not quite understand the map you propose as to me it does not seem to apply to the elements of the array I use to sort. Here a dump of the @ResultsFinal (3 records) before and after the sorting. If sorting for $OptOrderToDisplayTable=4, for example, you can see that the corresponding element of $VAR3 still remains undef . This fires an error by unac_string . Am I overseeing something in your code?
$VAR1 = [
841,
'bbb',
'',
'bbb',
'bbb',
undef,
undef,
undef,
'',
''
];
$VAR2 = [
842,
'bbb',
'',
'ccc',
'aaa',
undef,
undef,
undef,
'',
''
];
$VAR3 = [
850,
'bbb',
'',
'hhh',
undef,
undef,
undef,
undef,
'',
''
];
###After
$VAR1 = [
841,
'bbb',
'',
'bbb',
'bbb',
undef,
undef,
undef,
'',
''
];
$VAR2 = [
842,
'bbb',
'',
'ccc',
'aaa',
undef,
undef,
undef,
'',
''
];
$VAR3 = [
850,
'bbb',
'',
'hhh',
undef,
undef,
undef,
undef,
'',
''
];