title: Split Contents of String column in PySpark Dataframe
body: <p>I have a pyspark data frame whih has a column containing strings. I want to split this column into words</p>
  
  <p>Code:</p>
  
  <pre><code>&gt;&gt;&gt; sentenceData = sqlContext.read.load('file://sample1.csv', format='com.databricks.spark.csv', header='true', inferSchema='true')
  &gt;&gt;&gt; sentenceData.show(truncate=False)
  +---+---------------------------+
  |key|desc                       |
  +---+---------------------------+
  |1  |Virat is good batsman      |
  |2  |sachin was good            |
  |3  |but modi sucks big big time|
  |4  |I love the formulas        |
  +---+---------------------------+
  
  
  Expected Output
  ---------------
  
  &gt;&gt;&gt; sentenceData.show(truncate=False)
  +---+-------------------------------------+
  |key|desc                                 |
  +---+-------------------------------------+
  |1  |[Virat,is,good,batsman]              |
  |2  |[sachin,was,good]                    |
  |3  |....                                 |
  |4  |...                                  |
  +---+-------------------------------------+
  </code></pre>
  
  <p>How can I achieve this?</p>