python - Apache Spark - 特征提取 Word2Vec 示例和异常

Question

A.以下是我的配置:

操作系统:Windows 7

Spark 版本:1.4.1(1.4.0 中也存在问题)

语言:Python 和 Scala

B.示例源代码:

from pyspark import SparkContext
from pyspark.mllib.feature import Word2Vec

sc = SparkContext(appName='Word2Vec')
inp = sc.textFile("news2.txt").map(lambda row: row.split(" "))
word2vec = Word2Vec()
model = word2vec.fit(inp)  #Results in exception...

C.以下是堆栈跟踪:

Traceback (most recent call last):
  File "E:/StudySpark/Projects/Example/poc/poc5/main.py", line 10, in <module>
    model = word2vec.fit(inp)
  File "E:\StudySpark\Projects\Example\spark1.4.1\spark-1.4.1-bin-hadoop2.6\python\lib\pyspark.zip\pyspark\mllib\feature.py", line 519, in fit
  File "E:\StudySpark\Projects\Example\spark1.4.1\spark-1.4.1-bin-hadoop2.6\python\lib\pyspark.zip\pyspark\mllib\common.py", line 128, in callMLlibFunc
  File "E:\StudySpark\Projects\Example\spark1.4.1\spark-1.4.1-bin-hadoop2.6\python\lib\pyspark.zip\pyspark\mllib\common.py", line 121, in callJavaFunc
  File "E:\StudySpark\Projects\Example\spark1.4.1\spark-1.4.1-bin-hadoop2.6\python\lib\py4j-0.8.2.1-src.zip\py4j\java_gateway.py", line 538, in __call__
  File "E:\StudySpark\Projects\Example\spark1.4.1\spark-1.4.1-bin-hadoop2.6\python\lib\py4j-0.8.2.1-src.zip\py4j\protocol.py", line 300, in get_return_value
py4j.protocol.Py4JJavaError: An error occurred while calling o19.trainWord2Vec.
: java.util.NoSuchElementException: next on empty iterator
    at scala.collection.Iterator$$anon$2.next(Iterator.scala:39)
    at scala.collection.Iterator$$anon$2.next(Iterator.scala:37)
    at scala.collection.IterableLike$class.head(IterableLike.scala:91)
    at scala.collection.AbstractIterable.head(Iterable.scala:54)
    at org.apache.spark.mllib.feature.Word2VecModel.<init>(Word2Vec.scala:442)
    at org.apache.spark.mllib.feature.Word2Vec.fit(Word2Vec.scala:413)
    at org.apache.spark.mllib.feature.Word2Vec.fit(Word2Vec.scala:422)
    at org.apache.spark.mllib.api.python.PythonMLLibAPI.trainWord2Vec(PythonMLLibAPI.scala:560)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at py4j.reflection.MethodInvoker.invoke(MethodInvoker.java:231)
    at py4j.reflection.ReflectionEngine.invoke(ReflectionEngine.java:379)
    at py4j.Gateway.invoke(Gateway.java:259)
    at py4j.commands.AbstractCommand.invokeMethod(AbstractCommand.java:133)
    at py4j.commands.CallCommand.execute(CallCommand.java:79)
    at py4j.GatewayConnection.run(GatewayConnection.java:207)
    at java.lang.Thread.run(Thread.java:744)

有什么线索吗？

最诚挚的问候，

维沙尔

Answer 1

谢谢!熏肉。你让我走上了正确的道路。

输入文件中不存在在输入中重复一定次数的单词。默认情况下，出现在 word2vec 模型中的 token 的最小计数为 5(查看 YOUR_INSTALL_PATH\spark-1.4.1-bin-hadoop2.6\python\lib\pyspark.zip\pyspark\mllib 下 feature.py 中的类 word2vec\feature.py)

我的阅读，错误消息本来可以更好。

最诚挚的问候，维沙尔