title: Append row in pandas dataframe with values that were previously declared
body: <p>is there a way to save the columns and values you want to add before in a variable?<br>
  Like here:</p>
  
  <pre><code>var = "'r':0.1"
  print(var)
  
  dfnew = pd.DataFrame()
  for i in df.values:
        dfnew = dfnew.append({val}, ignore_index=True)
  </code></pre>