One or more of the elements of the array @positions is undefined. The easiest way to check this is like this:

use Data::Dump qw(pp);

pp([@positions]);

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This will give you a printout of the value of each element in array @positions. I expect we will see that some are "undef" meaning undefined. It will be these elements that are causing the problem.

In reply to Re^7: filtering an array by philiprbrenan
in thread filtering an array by prbndr

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