Date Manipulation with Pandas

Here's the task.

You need to generate dates between two ranges, extract the year, extract the month and extract the quarter number.

import pandas as pd

start = '1/1/2018'
end = '31/12/2020'

df = pd.DataFrame(columns=['Year', 'Month', 'Quarter']

Let's generate all the possible dates between start date and end date

dates = pd.date_range(start, end)

Now extract the year as

df.loc[:, 'Year'] = dates.to_period('Y')

Now extract the month as

df.loc[:, 'Month'] = dates.to_period('M').astype(str).str.replace('^\d*-', '', regex=True)

What's the reason for using regex?

Without the regex pandas would return quarter number as 2018-01. So using regex remove the beginning digits along with the - to get the month numbers.

Now extract the Quarter number as

df.loc[:, 'Quarter'] = dates.to_period('Q').astype(str).str.replace('^\d*', '', regex=True)

What the reason for using regex?

Without the regex pandas would return quarter number as 2018Q1. So using regex remove the beginning digits to get the quarter numbers.