I am not sure what you want to achieve as @entries will be empty after the while loop whatever you do inside... However, the following should do what you want (not tested as I could not think of sample data). 

while( @entries ) {
    my $top = shift @entries;
    @entries = map { compare_sub( $top, $_ ) > $user_defined_value ? $
+_ : () } @entries;
}

[download]

UPDATE: Reading the whole thread more carefully I realize that my proposal is essential the same (but more convoluted) as Tanktalus' grep above. Pls ignore...

In reply to Re: Iterating through an array using multiple loops and removing array elements by hdb
in thread Iterating through an array using multiple loops and removing array elements by BiochemPhD

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