title: Change the value of a column based on the value of another column with pandas
body: <p>To clarify I'll give an example:</p>
  <ul>
  <li>Dataframe has 2 columns: Currency and Price</li>
  <li>Currency has 3 unique values: EUR, GBP, USD</li>
  <li>I need to set the prices, as they are all in USD</li>
  <li>I need to multiply those values that are GBP and EUR with another double, i.e. 1.15 and 1.5 respectively.</li>
  </ul>