sum0

Add up every value in the list, returning 0 for an empty list.

תקציר

my $total = sum0 @values;
my $total = sum0 ();             # 0, not undef

מה מוחזר

The same number sum would produce, except that an empty list yields 0 instead of undef. This is almost always what callers want when adding up a list that may legitimately be empty.

דוגמאות

my $n = sum0 1..10;              # 55
my $n = sum0 ();                 # 0
my $n = sum0 grep { $_ > 0 } @x; # total of positives, 0 if none

הבדלים מן ה-upstream

Fully compatible with upstream.

ראו גם

• sum - the original; returns undef on empty input.

• product - identity element for multiplication (returns 1 on empty).