ValueError：无法使用pyspark一次在火花中运行多个SparkContext

Question

我是使用Spark的新手，我尝试在pyspark上运行此代码

from pyspark import SparkConf, SparkContext
import collections

conf = SparkConf().setMaster("local").setAppName("RatingsHistogram")
sc = SparkContext(conf = conf)

但是他直到我这个错误信息

Using Python version 3.5.2 (default, Jul  5 2016 11:41:13)
SparkSession available as 'spark'.
>>> from pyspark import SparkConf, SparkContext
>>> import collections
>>> conf = SparkConf().setMaster("local").setAppName("RatingsHistogram")
>>> sc = SparkContext(conf = conf)



   Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
      File "C:\spark\python\pyspark\context.py", line 115, in __init__
        SparkContext._ensure_initialized(self, gateway=gateway, conf=conf)
      File "C:\spark\python\pyspark\context.py", line 275, in _ensure_initialized
        callsite.function, callsite.file, callsite.linenum))
    ValueError: Cannot run multiple SparkContexts at once; existing SparkContext(app=PySparkShell, master=local[*]) created by getOrCreate at C:\spark\bin\..\python\pyspark\shell.py:43
    >>>

我有spark 2.1.1和python 3.5.2版本，我搜索发现它是sc中的问题，他看不懂，但是直到什么时候都没有，任何人都可以在这里找到帮助

Answer 1

你可以试试看

sc = SparkContext.getOrCreate();

Answer 2

您之前的会话仍在进行。你可以运行

sc.stop()

Answer 3

你可以试试：

sc = SparkContext.getOrCreate(conf=conf)