my @array = qw( a b c d c );

my $delete = 'c';

# search for index of elements which are equal to $delete
my @to_delete = grep { $array[$_] eq $delete } 0 .. $#array;

# delete elements from array (begin with biggest index, because we modify @array)
splice( @array, $_, 1 ) for reverse @to_delete;

# check what is left
print $_,"\n" for @array;