title: Apply function on Pandas dataframe
body: <p>I'm a newbie to pandas dataframe, and I wanted to apply a function to each column so that it computes for each element x, x/max of column. </p>
  
  <p>I referenced this question, but am having trouble accessing the maximum of each column. Thanks in advance
  <a href="https://stackoverflow.com/questions/12741092/pandas-dataframe-apply-function-to-all-columns">Pandas DataFrame: apply function to all columns</a></p>
  
  <p>Input:</p>
  
  <pre><code>      A  B  C  D
     0  8  3  5  8
     1  9  4  0  4
     2  5  4  3  8
     3  4  8  5  1
  </code></pre>
  
  <p>Output:</p>
  
  <pre><code>      A     B     C    D
     0  8/9  3/8  5/5  8/8
     1  9/9  4/8  0/5  4/8
     2  5/9  4/8  3/5  8/8
     3  4/9  8/8  5/5  1/8
  </code></pre>