$ perl -le'
use warnings;
use strict;

print "Enter number : ";
chomp( my $num = <STDIN> );
print "\$num = $num";

my @nums = split /(?<=[\d])/, $num;
print "\@nums = @nums";

my $i = 0;
for ( @nums ) {
    my $regex = qr/[$i]{$_}/;
    print "\$regex = $regex";
    print $num =~ $regex ? "true" : "false";
    $i++;
    }
'
Enter number : 
2020
$num = 2020
@nums = 2 0 2 0
$regex = (?-xism:[0]{2})
false
$regex = (?-xism:[1]{0})
true
$regex = (?-xism:[2]{2})
false
$regex = (?-xism:[3]{0})
true

##</code><code>##

$ perl -le'$x = () = "2020" =~ /[1]{0}/g; print $x'
5