in reply to Re: Keeping order, no duplicate and the complete keyset
in thread Keeping order, no duplicate and the complete keyset

The above assumes there are no dups in @big: 

my @big = qw( a b c d e f g h i a );
my @small = qw( f c d g );

my %found;
undef @found{@small};
my @wanted = ( @small, grep{ !exists $found{ $_ } } @big );

print("@wanted\n");
# f c d g a b e h i a

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The OP's version removed dups fom @big, and so does the following version: 

my @big = qw( a b c d e f g h i a );
my @small = qw( f c d g );

my %found;
$found{$_}++ foreach @small;
my @wanted = ( @small, grep{ !($found{$_}++) } @big );

print("@wanted\n");
# f c d g a b e h i

[download]

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Re^3: Keeping order, no duplicate and the complete keyset
by BrowserUk (Patriarch) on Dec 08, 2005 at 06:10 UTC

    Agreed. Your version can be simplified a little though. 

    my @big = qw( a b c d e f g h i a );
my @small = qw(f c d g c);
my %seen;
my @wanted = grep{ !$seen{ $_ }++ } @small, @big;

print "@wanted";
f c d g a b e h i

    [download]
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