Adding element to Array?

cthar has asked for the wisdom of the Perl Monks concerning the following question:

How do we add element to an array only if the element is non-empty? ie.... i have a list of element:

a

b 
c 

d 

a
a
c

d
c
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... etc so i want to add only a, b, c and d, ignoring the blank spaces. i tried:

  unless($list eq " ")
             {
                  push(@array, $list);
             }
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what am i doing wrong? thanks.

Again... i dont want to store/add the repeated element.... ie my array will contain only a, b , c and d. Thanks.