title: How to read files written by Spark with pandas?
body: <p>When Spark writes dateframe data to parquet file, Spark will create a directory which include several separate parquet files. Code for saving:</p>
  
  <pre><code>term_freq_df.write
              .mode("overwrite")
              .option("header", "true")
              .parquet("dir/to/save/to")
  </code></pre>
  
  <p>I need to read data from this directory with pandas:</p>
  
  <pre><code>term_freq_df = pd.read_parquet("dir/to/save/to") 
  </code></pre>
  
  <p>The error:</p>
  
  <pre><code>IsADirectoryError: [Errno 21] Is a directory: 
  </code></pre>
  
  <p>How to resolve this problem with the simple method that the two code samples could use same path of files?</p>