uniq

Remove subsequent duplicates by string equality, preserving order.

Registered under both uniq and uniqstr. Both treat elements as strings: two values are the same when their stringifications are byte-for-byte identical. The first occurrence of any given value wins; later duplicates are dropped.

Synopsis

my @subset = uniq    @values;
my @subset = uniqstr @values;
my $count  = uniq    @values;    # scalar context — count only

What you get back

In list context, the unique elements in first-seen order. In scalar context, the count of unique elements. undef compares equal to the empty string under uniqstr but is preserved as undef in the output by uniq.

Examples

my @u = uniq    qw( a b a c b );       # ('a', 'b', 'c')
my @u = uniqstr 'a', 'A';              # ('a', 'A') — case matters
my $n = uniq    qw( a b a c b );       # 3

Differences from upstream

Fully compatible with upstream.

See also

• uniqnum — compare as numbers rather than as strings.

• uniqint — compare as integers after truncation.