title: Strip / trim all strings of a dataframe
body: <p>Cleaning the values of a multitype data frame in python/pandas, I want to trim the strings. I am currently doing it in two instructions :</p>
  
  <pre><code>import pandas as pd
  
  df = pd.DataFrame([['  a  ', 10], ['  c  ', 5]])
  
  df.replace('^\s+', '', regex=True, inplace=True) #front
  df.replace('\s+$', '', regex=True, inplace=True) #end
  
  df.values
  </code></pre>
  
  <p>This is quite slow, what could I improve ?</p>