Neo4j：带密码的TF / IDF（和变体）

几周前，我写了一篇博客文章，介绍了如何使用scikit-learn在HIMYM成绩单上运行TF / IDF，以按情节找到最重要的短语，然后我很好奇在Neo4j中很难做到。

我首先将Wikipedia的TF / IDF示例之一翻译为cypher，以查看该算法的外观：

WITH 3 as termFrequency, 2 AS numberOfDocuments, 1 as numberOfDocumentsWithTerm
WITH termFrequency, log10(numberOfDocuments / numberOfDocumentsWithTerm) AS inverseDocumentFrequency
return termFrequency * inverseDocumentFrequency0.9030899869919435

接下来，我需要检查HIMYM情节成绩单，并提取每个情节中的短语及其对应的计数。我使用scikit-learn的CountVectorizer进行了此操作，并将结果写入了CSV文件。

这是该文件的预览：

$ head -n 10 data/import/words_scikit.csv
EpisodeId,Phrase,Count
1,2005,1
1,2005 seven,1
1,2005 seven just,1
1,2030,3
1,2030 kids,1
1,2030 kids intently,1
1,2030 narrator,1
1,2030 narrator kids,1
1,2030 son,1

现在，使用LOAD CSV工具将其导入Neo4j：

// phrases
USING PERIODIC COMMIT 1000
LOAD CSV WITH HEADERS FROM "file:///Users/markneedham/projects/neo4j-himym/data/import/words_scikit.csv" AS row
MERGE (phrase:Phrase {value: row.Phrase});

// episode -> phrase
USING PERIODIC COMMIT 1000
LOAD CSV WITH HEADERS FROM "file:///Users/markneedham/projects/neo4j-himym/data/import/words_scikit.csv" AS row
MATCH (phrase:Phrase {value: row.Phrase})
MATCH (episode:Episode {id: TOINT(row.EpisodeId)})
MERGE (episode)-[:CONTAINED_PHRASE {times:TOINT(row.Count)}]->(phrase);

现在，所有数据都可以转换为TF / IDF查询，以利用我们的图表。我们将从第1集开始：

match (e:Episode)
WITH COUNT(e) AS numberOfDocuments
match (p:Phrase)<-[r:CONTAINED_PHRASE]-(e:Episode {id: 1})
WITH numberOfDocuments, p, r.times AS termFrequency
MATCH (p)<-[:CONTAINED_PHRASE]->(otherEpisode)
WITH p, COUNT(otherEpisode) AS numberOfDocumentsWithTerm, numberOfDocuments, termFrequency
WITH p, numberOfDocumentsWithTerm,  log10(numberOfDocuments / numberOfDocumentsWithTerm) AS inverseDocumentFrequency, termFrequency, numberOfDocuments
RETURN p.value, termFrequency, numberOfDocumentsWithTerm, inverseDocumentFrequency, termFrequency * inverseDocumentFrequency AS score
ORDER BY score DESC
LIMIT 10==> +-----------------------------------------------------------------------------------+
==> | p.value                | termFrequency | numberOfDocumentsWithTerm | inverseDocumentFrequency | score              |
==> +-----------------------------------------------------------------------------------+
==> | "olives"               | 18            | 2                         | 2.0170333392987803       | 36.306600107378046 |
==> | "yasmine"              | 13            | 1                         | 2.3180633349627615       | 30.1348233545159   |
==> | "signal"               | 11            | 5                         | 1.6127838567197355       | 17.740622423917088 |
==> | "goanna"               | 10            | 4                         | 1.7160033436347992       | 17.16003343634799  |
==> | "flashback date"       | 6             | 1                         | 2.3180633349627615       | 13.908380009776568 |
==> | "scene"                | 17            | 37                        | 0.6989700043360189       | 11.88249007371232  |
==> | "flashback date robin" | 5             | 1                         | 2.3180633349627615       | 11.590316674813808 |
==> | "ted yasmine"          | 5             | 1                         | 2.3180633349627615       | 11.590316674813808 |
==> | "smurf pen1s"          | 5             | 2                         | 2.0170333392987803       | 10.085166696493902 |
==> | "eye patch"            | 5             | 2                         | 2.0170333392987803       | 10.085166696493902 |
==> +-----------------------------------------------------------------------------------+
==> 10 rows

我们计算出的分数不同于scikit-learn的分数，但是相对顺序似乎不错，所以很好。在Neo4j中计算这一点的整洁之处在于，我们现在可以更改等式的“逆文档”部分，例如，找出一个季节而不是一个情节中最重要的短语：

match (:Season) 
WITH COUNT(*) AS numberOfDocuments
match (p:Phrase)<-[r:CONTAINED_PHRASE]-(:Episode)-[:IN_SEASON]->(s:Season {number: "1"})
WITH p, SUM(r.times) AS termFrequency, numberOfDocuments
MATCH (p)<-[:CONTAINED_PHRASE]->(otherEpisode)-[:IN_SEASON]->(s:Season)
WITH p, COUNT(DISTINCT s) AS numberOfDocumentsWithTerm, termFrequency, numberOfDocuments
WITH p, numberOfDocumentsWithTerm,  log10(numberOfDocuments / numberOfDocumentsWithTerm) AS inverseDocumentFrequency, termFrequency, numberOfDocuments
RETURN p.value, termFrequency, numberOfDocumentsWithTerm, inverseDocumentFrequency, termFrequency * inverseDocumentFrequency AS score
ORDER BY score DESC
LIMIT 10==> +-----------------------------------------------------------------------------------+
==> | p.value         | termFrequency | numberOfDocumentsWithTerm | inverseDocumentFrequency | score              |
==> +-----------------------------------------------------------------------------------+
==> | "moby"          | 46            | 1                         | 0.9542425094393249       | 43.895155434208945 |
==> | "int"           | 71            | 3                         | 0.47712125471966244      | 33.87560908509603  |
==> | "ellen"         | 53            | 2                         | 0.6020599913279624       | 31.909179540382006 |
==> | "claudia"       | 104           | 4                         | 0.3010299956639812       | 31.307119549054043 |
==> | "ericksen"      | 59            | 3                         | 0.47712125471966244      | 28.150154028460083 |
==> | "party number"  | 29            | 1                         | 0.9542425094393249       | 27.67303277374042  |
==> | "subtitle"      | 27            | 1                         | 0.9542425094393249       | 25.76454775486177  |
==> | "vo"            | 47            | 3                         | 0.47712125471966244      | 22.424698971824135 |
==> | "ted vo"        | 47            | 3                         | 0.47712125471966244      | 22.424698971824135 |
==> | "future ted vo" | 45            | 3                         | 0.47712125471966244      | 21.47045646238481  |
==> +-----------------------------------------------------------------------------------+
==> 10 rows

从该查询中我们了解到，“ Moby”在整个系列中仅被提及一次，实际上所有提及都在同一集中。 “ int”的出现似乎更多是数据问题–在某些情节中，成绩单描述了位置，但在许多情节中却没有：

$ ack -iw "int" data/import/sentences.csv
2361,8,1,8,"INT. LIVING ROOM, YEAR 2030"
2377,8,1,8,INT. CHINESE RESTAURANT
2395,8,1,8,INT. APARTMENT
2412,8,1,8,INT. APARTMENT
2419,8,1,8,INT. BAR
2472,8,1,8,INT. APARTMENT
2489,8,1,8,INT. BAR
2495,8,1,8,INT. APARTMENT
2506,8,1,8,INT. BAR
2584,8,1,8,INT. APARTMENT
2629,8,1,8,INT. RESTAURANT
2654,8,1,8,INT. APARTMENT
2682,8,1,8,INT. RESTAURANT
2689,8,1,8,(Robin gets up and leaves restaurant) INT. HOSPITAL WAITING AREA

“ vo”代表语音，应该在停用词中删除它，因为它不会带来太多价值。之所以显示在这里，是因为这些笔录在表示Future Ted说话时的方式不一致。

让我们看一下最后一个赛季，看看票价如何：

match (:Season)
WITH COUNT(*) AS numberOfDocuments
match (p:Phrase)<-[r:CONTAINED_PHRASE]-(:Episode)-[:IN_SEASON]->(s:Season {number: "9"})
WITH p, SUM(r.times) AS termFrequency, numberOfDocuments
MATCH (p)<-[:CONTAINED_PHRASE]->(otherEpisode:Episode)-[:IN_SEASON]->(s:Season)
WITH p, COUNT(DISTINCT s) AS numberOfDocumentsWithTerm, termFrequency, numberOfDocuments
WITH p, numberOfDocumentsWithTerm,  log10(numberOfDocuments / numberOfDocumentsWithTerm) AS inverseDocumentFrequency, termFrequency, numberOfDocuments
RETURN p.value, termFrequency, numberOfDocumentsWithTerm, inverseDocumentFrequency, termFrequency * inverseDocumentFrequency AS score
ORDER BY score DESC
LIMIT 10==> +-----------------------------------------------------------------------------------+
==> | p.value              | termFrequency | numberOfDocumentsWithTerm | inverseDocumentFrequency | score              |
==> +-----------------------------------------------------------------------------------+
==> | "ring bear"          | 28            | 1                         | 0.9542425094393249       | 26.718790264301095 |
==> | "click options"      | 26            | 1                         | 0.9542425094393249       | 24.810305245422448 |
==> | "thank linus"        | 26            | 1                         | 0.9542425094393249       | 24.810305245422448 |
==> | "vow"                | 39            | 2                         | 0.6020599913279624       | 23.480339661790534 |
==> | "just click"         | 24            | 1                         | 0.9542425094393249       | 22.901820226543798 |
==> | "rehearsal dinner"   | 23            | 1                         | 0.9542425094393249       | 21.947577717104473 |
==> | "linus"              | 36            | 2                         | 0.6020599913279624       | 21.674159687806647 |
==> | "just click options" | 22            | 1                         | 0.9542425094393249       | 20.993335207665147 |
==> | "locket"             | 32            | 2                         | 0.6020599913279624       | 19.265919722494797 |
==> | "cassie"             | 19            | 1                         | 0.9542425094393249       | 18.13060767934717  |
==> +-----------------------------------------------------------------------------------+

Barney＆Robin的婚礼有几个特定的短语（“誓言”，“圆环熊”，“排练晚宴”），因此将这些放在首位是有道理的。这里的“ linus”主要是指酒吧中与Lily进行交互的服务器，尽管对笔录进行了快速搜索后发现她还有一个Linus叔叔！

$ ack -iw "linus" data/import/sentences.csv  | head -n 5
18649,61,3,17,Lily: Why don't we just call Duluth Mental Hospital and say my Uncle Linus can live with us?
59822,185,9,1,Linus.
59826,185,9,1,"Are you my guy, Linus?"
59832,185,9,1,Thank you Linus.
59985,185,9,1,"Thank you, Linus."
...

通过执行此练习，我认为TF / IDF是探索非结构化数据的一种有趣方式，但是对于一个对我们来说真的很有趣的短语，它应该出现在多个情节/季节中。

实现该目标的一种方法是对这些功能进行更多加权，因此我将在下一步进行尝试。