Perl中获取两个字符串列表的交集 [英] Get the intersection of two lists of strings in Perl

问题描述

在第 4 章第 4.8 节(计算唯一列表的联合、交集或差异)中，Perl Cookbook 提供了获取两个整数列表交集的技术:

In Chapter 4, Section 4.8 (Computing Union, Intersection, or Difference of Unique Lists), the Perl Cookbook provides this technique for getting the intersection of two lists of integers:

@a = (1, 3, 5, 6, 7, 8);
@b = (2, 3, 5, 7, 9);
...
foreach $e (@a, @b) {
    $union{$e}++ && $isect{$e}++
}
@union = keys %union;
@isect = keys %isect;

我希望对两个字符串列表执行此操作(不区分大小写).请问有什么有效的方法吗?

I want this to be done (case-insensitively) for two lists of strings. Any efficient method, please?

推荐答案

Array::Utils 正是您要找的.

Array::Utils is what you're looking for.

use Array::Utils qw(:all);

my @a = qw( a b c d );
my @b = qw( c d e f );

my @isect = intersect(@a, @b);
print join(",",@isect) . "\n";

这会产生预期的输出

c,d

我没有注意到您希望不区分大小写地完成此操作.在这种情况下，您可以将 @a 替换为 map{lc}@a(同样也可以替换为 @b).

I didn't notice that you wanted this done case-insensitively. In that case, you can replace @a with map{lc}@a (and likewise with @b).

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