Appending a list or series to a pandas DataFrame as a row?

Question

So I have initialized an empty pandas DataFrame and I would like to iteratively append lists (or Series) as rows in this DataFrame. What is the best way of doing this?

Answer 1

Here's a function that, given an already created dataframe, will append a list as a new row. This should probably have error catchers thrown in, but if you know exactly what you're adding then it shouldn't be an issue.

import pandas as pd
import numpy as np

def addRow(df,ls):
    """
    Given a dataframe and a list, append the list as a new row to the dataframe.

    :param df:  The original dataframe
    :param ls:  The new row to be added
    :return:  The dataframe with the newly appended row
    """

    numEl = len(ls)

    newRow = pd.DataFrame(np.array(ls).reshape(1,numEl), columns = list(df.columns))

    df = df.append(newRow, ignore_index=True)

    return df