Beyond this particular comparison, is the formatting of $es important? If not, I'd convert it to a plain numeric format, then do a numeric comparison.

$str =~ tr/0-9.+-//cd ; # Not perfect, but probably good enough.
if ( $str == 0 } { ... }
[download]

_______________
DamnDirtyApe

Those who know that they are profound strive for clarity. Those who
would like to seem profound to the crowd strive for obscurity.
            --Friedrich Nietzsche