title: Looping the 'nearest neighbour' function over rainfall data in each column to handle NaN
body: <ol>
  <li><p>I have the dataset of rainfall data that has NaN (mm) rainfall values for each date. Rainfall datas are from different stations with Longitude and Latitude.</p>
  </li>
  <li><p>I would like to know how I can loop and fill the NaN values using rainfall value from another nearby rainfall station on the same date.</p>
  </li>
  <li><p>I would then like to keep the final csv product with all the NaNs replaced with 'nearest neighbour' values.</p>
  </li>
  </ol>
  <p>Dataset: <a href="https://docs.google.com/spreadsheets/d/1D_k1iB5U-qE2FRRi4MYJ80815YW5FI5jpV0F1uy1ddk/edit#gid=186097297" rel="nofollow noreferrer">https://docs.google.com/spreadsheets/d/1D_k1iB5U-qE2FRRi4MYJ80815YW5FI5jpV0F1uy1ddk/edit#gid=186097297</a></p>
  <p>Thank you so much for your help!</p>