Perl段落n-gram

$body = 'the quick brown fox jumps over the lazy dog';

我想把这句话变成’关键词’的哈希值,但我想允许多词关键词;我有以下内容来获取单字关键字：

$words{$_}++ for $body =~ m/(w+)/g;

完成后,我有一个如下所示的哈希：

'the' => 2,'quick' => 1,'brown' => 1,'fox' => 1,'jumps' => 1,'over' => 1,'lazy' => 1,'dog' => 1

下一步,以便我可以获得双字关键字,如下所示：

$words{$_}++ for $body =~ m/(w+ w+)/g;

但这只会得到每一个“其他”对;看起来像这样：

'the quick' => 1,'brown fox' => 1,'jumps over' => 1,'the lazy' => 1

我还需要一个字偏移量：

'quick brown' => 1,'fox jumps' => 1,'over the' => 1

有没有比以下更容易的方法？

my $orig_body = $body;
# single word keywords
$words{$_}++ for $body =~ m/(w+)/g;
# double word keywords
$words{$_}++ for $body =~ m/(w+ w+)/g;
$body =~ s/^(w+)//;
$words{$_}++ for $body =~ m/(w+ w+)/g;
$body = $orig_body;
# triple word keywords
$words{$_}++ for $body =~ m/(w+ w+ w+)/g;
$body =~ s/^(w+)//;
$words{$_}++ for $body =~ m/(w+ w+ w+)/g;
$body = $orig_body;
$body =~ s/^(w+ w+)//;
$words{$_}++ for $body =~ m/(w+ w+ w+)/g;