title: convert pandas dataframe with None;s in it to spark dataframe
body: <p>How do I convert pandas data frame with few None's in it to pyspark dataframe?</p>
  <p>Pandas Dataframe  -pandas_df :</p>
  <pre><code>0    30832
  1      859
  2     None
  3    11982
  4     None
  5    18218
  6    21232
  7    26804
  8    25144
  9    15921 
  </code></pre>
  <p>creating schema like below - mySchema:</p>
  <pre><code>StructField(&quot;column_count&quot;, LongType(), True)
  </code></pre>
  <p>applying schema:</p>
  <pre><code>spark.createDataFrame(pandas_df, mySchema)
  </code></pre>
  <blockquote>
  <p>Error : TypeError: field term_ins_year_cnt: LongType can not accept
  object 30832.0 in type &lt;class 'float'&gt;</p>
  </blockquote>