2. Initialize the spark

 

reference:
 
 we highly recommend you to switch to use Dataset, which has better performance than RDD
 
The most important task : create SparkContext
    Connected to the Spark "cluster": local, standalone, yarn, mesos
    To create RDD, broadcast variable to the cluster by SparkContext
    
    We need to create a SparkConf objects before creating SparkContext
    
    bin directory into the spark of
    ./pyspark
    
    
    In the PySpark shell, a special interpreter-aware SparkContext is already created for you, in the variable called sc.
    
    
    appName
    ./pyspark --help View Help
    
    
RDD way to create
    Parallelized Collections
        data = [1, 2, 3, 4, 5]       distData = sc.parallelize(data)
    External Datasets
        distFile = sc.textFile("file:////root/app/test/hello.txt")
 
 
    If using a path on the local filesystem, the file must also be accessible at the same path on worker nodes
 

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Origin www.cnblogs.com/huangguoming/p/10929385.html