title: Reading and editing excel files with pandas
body: <p>So, I'm reading xlsx files and I need to select 3 specific columns, then rename them, and transfer the first 100 rows of each column to a new xlsx file, deleting them from the original one.</p>
  
  <p>My code as of now is reading from a manually edited xlsx file, where I rename the columns, select the first 100 of them (except for the header), etc: </p>
  
  <pre><code>df = pandas.read_excel('test.xlsx', names=['date', 'value', 'source'])
  df['date'] = pandas.to_datetime(df['date'], format='%b %d %Y.%f').astype(str)
  
  print(df.head(5))
  </code></pre>
  
  <p>Which returns, as expected: </p>
  
  <pre><code>         date    value               source
  
  0  2018-05-01      1                xxxxxxx
  1  2018-05-01      1      xxxxxxxxxxxxxxxxx
  2  2018-05-02      1      xxxxxxxxxxxxxxxxx
  3  2018-05-02      1      xxxxxxxxxxxxxxxxx
  4  2018-05-03      1     xxxxxxxxxxxxxxxxxx
  </code></pre>
  
  <p>Is there a way to automatically read and edit the xlsx file with pandas? Other libs? I'm new to python and I'm really lost here :(</p>