如何获得两个字符串数组的相对补码？

Question

my @A = ("aa","bb");

my @B = ("aa","cc");

与Set的相对补码相同的概念。 （A-B）输出应为“ bb”。我不想只使用Perl的内置功能来使用Perl的任何外部模块。

Answer 1

my @A = ("aa","bb"); 
my @B = ("aa","cc");

# make a hash with all the elements of @B as keys
my %B;
@B{@B} = ();

my @complement = grep { ! exists $B{$_} } @A;