title: Sort values in a Pandas data frame by a temporary variable
body: <p>In R, I can use <code>dplyr::arrange</code> to sort a data frame by a temporary variable. For example, using the NYC <code>flights</code> dataset in the <code>nycflights13</code> package, I can sort by velocity by computing this value from the <code>distance</code> and <code>air_time</code> columns:</p>
  
  <pre><code>library(nycflights13)
  arrange(flights, distance / air_time)
  </code></pre>
  
  <p>Is it possible to achieve this with Pandas (without explicitly creating a new column, sorting by that column, and then removing this column again)?</p>