title: make upper case and replace space in column dataframe
body: <p>for a specific column of a pandas dataframe I would like to make the elements all uppercase and replace the spaces</p>
  
  <pre><code>import pandas as pd
  
  df = pd.DataFrame(data=[['AA 123',00],[99,10],['bb 12',10]],columns=['A','B'],index=[0,1,2])
  
  # find elements 'A' that are string
  temp1 = [isinstance(s, str) for s in df['A'].values]
  
  # Make upper case and replace any space
  temp2 = df['A'][temp1].str.upper()
  temp2 = temp2.str.replace(r'\s', '')
  
  # replace in dataframe
  df['A'].loc[temp2.index] = temp2.values
  </code></pre>
  
  <p>I get</p>
  
  <pre><code>C:\ProgramData\Anaconda3\lib\site-packages\pandas\core\indexing.py:194: SettingWithCopyWarning: 
  A value is trying to be set on a copy of a slice from a DataFrame
  
  See the caveats in the documentation: http://pandas.pydata.org/pandas-docs/stable/indexing.html#indexing-view-versus-copy
    self._setitem_with_indexer(indexer, value)
  </code></pre>
  
  <p>Any suggestion to avoid this warning or any better way to do what I am trying to do?</p>