On the other extreme of the spectrum, I could say 
for (-$#array .. 0) {
    splice (@array,$_,1) if ($array[$_] =~ /^\#/)
}

[download]

That doesn't do what you seem to think it does.   It starts with the second element of the array, iterates up to the last element of the array and finally ends with the first element of the array.   If you splice elements out of the array then the elements remaining will be moved and won't be removed by subsequent splices.

What you need to do is start at the last element of the array and iterate towards the first element: 

for ( reverse 0 .. $#array ) {
    splice @array, $_, 1 if $array[ $_ ] =~ /^\#/;
}

[download]

In reply to Re: Efficient array element deletion by jwkrahn
in thread Efficient array element deletion by kennethk

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