title: How to update the values in csv file?
body: <p>I have a csv file and I want to change the values in the column <code>A1</code>, <code>A2</code> <code>A3</code> if the value is the half value or more of the total. In other words, for like Value 1 in A1, I want that 50 to be the total.
  I want something like this:</p>
  <p><img src="https://i.stack.imgur.com/ZalMY.png" alt="What I want" /></p>
  <p>And I have something like this:</p>
  <p><img src="https://i.stack.imgur.com/xOE6g.png" alt="How it is" /></p>
  <p>I've only did this:</p>
  <pre class="lang-py prettyprint-override"><code>df=pd.read_csv(&quot;book.csv&quot;,index_col=0)
  print(df)
  </code></pre>