Python pandas: fill a dataframe row by row

Question

The simple task of adding a row to a pandas.DataFrame object seems to be hard to accomplish. There are 3 stackoverflow questions relating to this, none of which

Answer 1

My approach was, but I can't guarantee that this is the fastest solution.

df = pd.DataFrame(columns=["firstname", "lastname"])
df = df.append({
     "firstname": "John",
     "lastname":  "Johny"
      }, ignore_index=True)