Python: Order Dates that are in the format: %B %Y

Question

I have a df with dates in the format %B %Y (e.g. June 2021, December 2022 etc.)

Date	Price
Apr 2022	2
Dec 2021	8

I am trying to sort dates in order of oldest to newest but when I try:

.sort_values(by='Date', ascending=False)

it is ordering in alphabetical order.

The 'Date' column is an Object.

Answer 1

• ascending=False will sort from newest to oldest, but you are asking to sort oldest to newest, so you don't need that option;
• there is a key option to specify how to parse the values before sorting them;
• you may or may not want option ignore_index=True, which I included below.

We can use the key option to parse the values into datetime objects with pandas.to_datetime.

import pandas as pd

df = pd.DataFrame({'Date': ['Apr 2022', 'Dec 2021', 'May 2022', 'May 2021'], 'Price': [2, 8, 12, 15]})

df = df.sort_values(by='Date', ignore_index=True, key=pd.to_datetime)

print(df)
#        Date  Price
# 0  May 2021     15
# 1  Dec 2021      8
# 2  Apr 2022      2
# 3  May 2022     12

Relevant documentation:

• DataFrame.sort_values;
• to_datetime.