使用pyspark计算所有可能的单词对

Question

我有一个文本文件。我需要在整个文档中找到重复单词对的可能计数。例如，我有下面的word文档。该文档有两行，每行之间用“;”分隔。文件：

My name is Sam My name is Sam My name is Sam;
My name is Sam;

我正在研究成对单词计数。预期结果是：

[(('my', 'my'), 3), (('name', 'is'), 7), (('is', 'name'), 3), (('sam', 'sam'), 3), (('my', 'name'), 7), (('name', 'sam'), 7), (('is', 'my'), 3), (('sam', 'is'), 3), (('my', 'sam'), 7), (('name', 'name'), 3), (('is', 'is'), 3), (('sam', 'my'), 3), (('my', 'is'), 7), (('name', 'my'), 3), (('is', 'sam'), 7), (('sam', 'name'), 3)]

如果我使用：

wordPairCount = rddData.map(lambda line: line.split()).flatMap(lambda x: [((x[i], x[i + 1]), 1) for i in range(0, len(x) - 1)]).reduceByKey(lambda a,b:a + b)

我得到连续单词的成对单词及其重复出现的次数。

如何将每个单词与该行中的每个其他单词配对，然后在所有行中搜索相同的单词对？

有人可以看看吗？谢谢

Answer 1

您的输入字符串：

# spark is SparkSession object
s1 = 'The Adventure of the Blue Carbuncle The Adventure of the Blue Carbuncle The Adventure of the Blue Carbuncle; The Adventure of the Blue Carbuncle;'

# Split the string on ; and I parallelize it to make an rdd
rddData = spark.sparkContext.parallelize(rdd_Data.split(";"))

rddData.collect()
# ['The Adventure of the Blue Carbuncle The Adventure of the Blue Carbuncle The Adventure of the Blue Carbuncle', ' The Adventure of the Blue Carbuncle', '']

import itertools

final = (
    rddData.filter(lambda x: x != "")
        .map(lambda x: x.split(" "))
        .flatMap(lambda x: itertools.combinations(x, 2))
        .filter(lambda x: x[0] != "")
        .map(lambda x: (x, 1))
        .reduceByKey(lambda x, y: x + y).collect()
)
# [(('The', 'of'), 7), (('The', 'Blue'), 7), (('The', 'Carbuncle'), 7), (('Adventure', 'the'), 7), (('Adventure', 'Adventure'), 3), (('of', 'The'), 3), (('the', 'Adventure'), 3), (('the', 'the'), 3), (('Blue', 'The'), 3), (('Carbuncle', 'The'), 3), (('Adventure', 'The'), 3), (('of', 'the'), 7), (('of', 'Adventure'), 3), (('the', 'The'), 3), (('Blue', 'Adventure'), 3), (('Blue', 'the'), 3), (('Carbuncle', 'Adventure'), 3), (('Carbuncle', 'the'), 3), (('The', 'The'), 3), (('of', 'Blue'), 7), (('of', 'Carbuncle'), 7), (('of', 'of'), 3), (('Blue', 'Carbuncle'), 7), (('Blue', 'of'), 3), (('Blue', 'Blue'), 3), (('Carbuncle', 'of'), 3), (('Carbuncle', 'Blue'), 3), (('Carbuncle', 'Carbuncle'), 3), (('The', 'Adventure'), 7), (('The', 'the'), 7), (('Adventure', 'of'), 7), (('Adventure', 'Blue'), 7), (('Adventure', 'Carbuncle'), 7), (('the', 'Blue'), 7), (('the', 'Carbuncle'), 7), (('the', 'of'), 3)]

1. 从第一次拆分中删除任何空格
2. 将x分隔为一个用空格分隔的字符串
3. 使用itertools.combinations创建两个元素的组合（flatMap将行中的每个单词与其他单词配对）
4. 就像减少字数统计一样映射和减少