title: How to extract a single (column/row) value from a dataframe using PySpark?
body: <p>Here's my spark code. It works fine and returns 2517. All I want to do is to print "2517 degrees"...but I'm not sure how to extract that 2517 into a variable. I can only display the dataframe but not extract values from it. Sounds super easy but unfortunately I'm stuck! Any help will be appreciated. Thanks!</p>
  
  <pre><code>df = sqlContext.read.format("csv").option("header", "true").option("inferSchema", "true").option("delimiter", "\t").load("dbfs:/databricks-datasets/power-plant/data")
  
  df.createOrReplaceTempView("MyTable")
  
  df = spark.sql("SELECT COUNT (DISTINCT AP) FROM MyTable")
  
  display(df)
  </code></pre>