With split

my $string = "12 34 56 78 90 98 76 54 32 10";
my $n = 3;
print+ (split( /[^\d+]/, $string))[$n-1];
# output => 56

my $string ='abcabbcabbbbcabcabbcab';
my $n = 3;
print+ (split( /[^(?:ab+)]/, $string ))[$n-1];
# output => abbbb
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