pyspark 在一次加载中加载多个分区文件

Question

我正在尝试在一次加载中加载多个文件。它们都是分区文件当我尝试使用 1 个文件时它可以工作，但是当我列出 24 个文件时，它给了我此错误，除了在加载后进行联合之外，我找不到任何限制和解决方法的文档。还有其他选择吗？

下面的代码以重现问题：

basepath = '/file/' 
paths = ['/file/df201601.orc', '/file/df201602.orc', '/file/df201603.orc',  
         '/file/df201604.orc', '/file/df201605.orc', '/file/df201606.orc',  
         '/file/df201604.orc', '/file/df201605.orc', '/file/df201606.orc',  
         '/file/df201604.orc', '/file/df201605.orc', '/file/df201606.orc',  
         '/file/df201604.orc', '/file/df201605.orc', '/file/df201606.orc',  
         '/file/df201604.orc', '/file/df201605.orc', '/file/df201606.orc',  
         '/file/df201604.orc', '/file/df201605.orc', '/file/df201606.orc',  
         '/file/df201604.orc', '/file/df201605.orc', '/file/df201606.orc', ]   
df = sqlContext.read.format('orc') 
               options(header='true',inferschema='true',basePath=basePath)
               .load(*paths)

收到的错误：

 TypeError                                 Traceback (most recent call last)
 <ipython-input-43-7fb8fade5e19> in <module>()
---> 37 df = sqlContext.read.format('orc')                .options(header='true', inferschema='true',basePath=basePath)                .load(*paths)
     38 
TypeError: load() takes at most 4 arguments (24 given)

Answer 1

如官方文档中所述，要读取多个文件，您应该传递一个list：

path – 文件系统支持的数据源的可选字符串或字符串列表。

所以在你的情况下：

(sqlContext.read
    .format('orc') 
    .options(basePath=basePath)
    .load(path=paths))

参数解包(*(只有在用可变参数定义时才有意义load，例如：

def load(this, *paths):
    ...