title: Python Combining two columns into one based on each columns value
body: <p>I am working from <a href="https://www.kaggle.com/harlfoxem/housesalesprediction" rel="nofollow noreferrer">this</a> dataset and I would like to combine yr_built and yr_renovated into one, preferably to yr_built, based on this: if the value in yr_renovated is bigger than 0, then I would like to have this value, otherwise the yr_built's value.</p>
  
  <p>Can you please help me on this?</p>
  
  <p>Thank you!</p>