我有以下数据框架
+------------------------------------------------+
|filtered |
+------------------------------------------------+
|[human, interface, computer] |
|[survey, user, computer, system, response, time]|
|[eps, user, interface, system] |
|[system, human, system, eps] |
|[user, response, time] |
|[trees] |
|[graph, trees] |
|[graph, minors, trees] |
|[graph, minors, survey] |
+------------------------------------------------+
在上面的列上运行CountVectorizer后，我将获得以下输出
+------------------------------------------------+-------------------
--------------------------+
|filtered |features |
+------------------------------------------------+---------------------------------------------+
|[human, interface, computer] |(12,[4,7,9],[1.0,1.0,1.0]) |
|[survey, user, computer, system, response, time]|(12,[0,2,6,7,8,11],[1.0,1.0,1.0,1.0,1.0,1.0])|
|[eps, user, interface, system] |(12,[0,2,4,10],[1.0,1.0,1.0,1.0]) |
|[system, human, system, eps] |(12,[0,9,10],[2.0,1.0,1.0]) |
|[user, response, time] |(12,[2,8,11],[1.0,1.0,1.0]) |
|[trees] |(12,[1],[1.0]) |
|[graph, trees] |(12,[1,3],[1.0,1.0]) |
|[graph, minors, trees] |(12,[1,3,5],[1.0,1.0,1.0]) |
|[graph, minors, survey] |(12,[3,5,6],[1.0,1.0,1.0]) |
+------------------------------------------------+---------------------------------------------+
现在我想在功能列上运行地图功能，然后将其转换为类似的东西
+------------------------------------------------+--------------------------------------------------------+
|features |transformed |
+------------------------------------------------+--------------------------------------------------------+
|(12,[4,7,9],[1.0,1.0,1.0]) |["1 4 1", "1 7 1", "1 9 1"] |
|(12,[0,2,6,7,8,11],[1.0,1.0,1.0,1.0,1.0,1.0]) |["2 0 1", "2 2 1", "2 6 1", "2 7 1", "2 8 1", "2 11 1"] |
|(12,[0,2,4,10],[1.0,1.0,1.0,1.0]) |["3 0 1", "3 2 1", "3 4 1", "3 10 1"] |
[TRUNCATED]
转换功能的方式是从功能中获取中间数组，然后从中创建子阵列。例如，在features列的第1行和Col 1中，我们有
(12,[4,7,9],[1.0,1.0,1.0])
现在以[4,7,9]为中间数组，并将其FREQ与第三列（即[1.0,1.0,1.0]预启动" 1"）进行比较，以获取以下输出：
["1 4 1", "1 7 1", "1 9 1"]
通常看起来像这样：
["RowNumber MiddleFeatEl CorrespondingFreq", ....]
我无法从CountVectorizer通过应用地图功能生成的功能列分别提取中间和 last freq list list P>
所以以下是地图代码：
def corpus_create(feats):
return feats[1] # Here i want to get [4,7,9] instead of 1 single feat score.
corpus_udf = udf(lambda feats: corpus_create(feats), StringType())
df3 = df.withColumn("corpus", corpus_udf("features"))
行数本质上是毫无意义的，但是如果您不介意：
def f(x):
row, i = x
jvs = (
# SparseVector
zip(row.features.indices, row.features.values) if hasattr(row.features, "indices")
# DenseVector
else enumerate(row.features.toArray()))
s = ["{} {} {}".format(i, j, v)
for j, v in jvs if v]
return row + (s, )
df.rdd.zipWithIndex().map(f).toDF(df.columns + ["transformed"])