Pandas Series dt.is_quarter_start | Check if a Date is First day of Quarter

Pandas dt.is_quarter_start attribute returns a boolean value indicating whether the date is the first day of a quarter.

Example:

Python3

import pandas as pd
sr = pd.Series(['2012-4-1', '2019-7-18 12:30', '2008-02-2 10:30',
               '2010-4-22 09:25', '2019-1-1 00:00'])
idx = ['Day 1', 'Day 2', 'Day 3', 'Day 4', 'Day 5']
sr.index = idx
sr = pd.to_datetime(sr)
result = sr.dt.is_quarter_start
print(result)

Output :

Syntax

Syntax: Series.dt.is_quarter_start 

Parameter: None 

Returns: Series with boolean values

How to Check if Date is First in it’s Quarter in Pandas Series

To check if a Date is the first date in its respective quarter in the Pandas Series, we use the dt.is_quarter_start attribute of the Pandas Library in Python.

Let us understand it better with an example:

Example

Use the Series.dt.is_quarter_start attribute to check if the dates in the underlying data of the given series object are the first day of the quarter.

Python3

# importing pandas as pd
import pandas as pd

# Creating the Series
sr = pd.Series(pd.date_range('2012-4-1 00:00',
                    periods = 5, freq = 'W'))

# Creating the index
idx = ['Day 1', 'Day 2', 'Day 3', 'Day 4', 'Day 5']

# set the index
sr.index = idx

# Print the series
print(sr)

Output :

Now we will use the dt.is_quarter_start attribute to check if the dates in the given series object is the first day of the quarter or not.

Python3

# check if dates are the first
# day of the quarter
result = sr.dt.is_quarter_start

# print the result
print(result)

Output :

As we can see in the output, the dt.is_quarter_start attribute has successfully accessed and returned boolean values indicating whether the dates are the first day of the quarter.