Python Create List Of Dates Within Range

This step-by-step guide lets you know how to create a list of dates within a range of dates in Python. For example, you may want to create a list of dates from 1st January 2022 to 30th June 2022. Or you may want to generate a list of dates from today to the next/previous 30 days.

Goals of this lesson:

• Generate a list of dates between two dates.
• Iterate through a range of dates.
• Generate a list of dates between two dates using pandas.
• Generate a list of dates so that the difference between each date is 1 month.

How to create a list of dates within a date range in Python

Example: create a list of dates within a range of dates

In this example, we specify two dates and create a list with all the dates in between them.

from datetime import date, timedelta

start_dt = date(2022, 6, 10)
end_dt = date(2022, 6, 15)

# difference between current and previous date
delta = timedelta(days=1)

# store the dates between two dates in a list
dates = []

while start_dt <= end_dt:
    # add current date to list by converting  it to iso format
    dates.append(start_dt.isoformat())
    # increment start date by timedelta
    start_dt += delta

print('Dates between', start_dt, 'and', end_dt)
print(dates)

Output:

Dates between 2022-06-16 and 2022-06-15

[datetime.date(2022, 6, 10), datetime.date(2022, 6, 11), datetime.date(2022, 6, 12), datetime.date(2022, 6, 13), datetime.date(2022, 6, 14), datetime.date(2022, 6, 15)]

Example 2: Create a list of the next 7 dates starting from the current date

Here we’ll use list comprehension to get the desired result.

import datetime

num_of_dates = 3
start = datetime.datetime.today()
date_list = [start.date() + datetime.timedelta(days=x) for x in range(num_of_dates)]
print('Next 3 days starting from today')
print(date_list)

Output:

Next 3 days starting from today
[datetime.date(2023, 2, 16), datetime.date(2023, 2, 17), datetime.date(2023, 2, 18)]

Example 3: Create a list of the previous 7 dates starting from the current date

import datetime

num_of_dates = 3
start = datetime.datetime.today()
date_list = [start.date() - datetime.timedelta(days=x) for x in range(num_of_dates)]
print('Previous 3 days starting from today')
print(date_list)

Output:

Previous 3 days starting from today
[datetime.date(2023, 2, 16), datetime.date(2023, 2, 15), datetime.date(2023, 2, 14)]

Generate a date range using pandas

We can also use the pandas date_range() to create a list of dates within a date range.

We need to pass the following parameters to the date_range() function.

• start: str or datetime object. The Start date (Left bound for generating dates).
• end: str or datetime object. The end date (Right bound for generating dates).
• periods: Number of periods to generate.
• freq: default ‘D’, which is a calendar day. i.e., Each next date in the list is generated by adding one day to a preceding date. Read this for a list of all frequency aliases.

Of the four parameters, the start, end, periods, and freq, exactly three must be specified.

Example 1: Create a date range by specifying the start and end date with the default daily frequency.

from datetime import datetime
import pandas as pd

# start date
start_date = datetime.strptime("2022-10-17", "%Y-%m-%d")
end_date = datetime.strptime("2022-10-23", "%Y-%m-%d")

# difference between each date. D means one day
D = 'D'

date_list = pd.date_range(start_date, end_date, freq=D)
print(f"Creating list of dates starting from {start_date} to {end_date}")
print(date_list)

# if you want dates in string format then convert it into string
print(date_list.strftime("%Y-%m-%d"))

Output:

Creating list of dates starting from 2022-10-17 00:00:00 to 2022-10-23 00:00:00

DatetimeIndex(['2022-10-17', '2022-10-18', '2022-10-19', '2022-10-20',
               '2022-10-21', '2022-10-22', '2022-10-23'],
              dtype='datetime64[ns]', freq='D')

Index(['2022-10-17', '2022-10-18', '2022-10-19', '2022-10-20', '2022-10-21',
       '2022-10-22', '2022-10-23'],
      dtype='object')

Example 2: create a date range by specifying the start date and number of dates you want

from datetime import datetime
import pandas as pd

start_date = datetime.strptime("2022-10-20", "%Y-%m-%d")

# periods means how many dates you want
date_list = pd.date_range(start_date, periods=5, freq='D')

print(f"Creating list of 5 dates starting from {start_date}")
print(date_list)

Output:

Creating list of, 5 dates starting from 2022-10-20 00:00:00
DatetimeIndex(['2022-10-20', '2022-10-21', '2022-10-22', '2022-10-23',
               '2022-10-24'],
              dtype='datetime64[ns]', freq='D')

Example 3: Createa monthly date range

Let’s see how to create a date range on specific dates for each month. We need to change the freq (frequency) to ‘M’ (month-end frequency).

from datetime import datetime
import pandas as pd

start_date = datetime.strptime("2022-10-20", "%Y-%m-%d")
date_list = pd.date_range(start_date, periods=5, freq='M')

print(f"Creating list of 5 dates starting from {start_date} with difference in each date is 1 month")
print(date_list)

# frequency of 6 months
print(f"Creating list of 5 dates starting from {start_date} with difference in each date is 6 month")
date_list = pd.date_range(start_date, periods=5, freq='6M')
print(date_list)

Output:

Creating list of 5 dates starting from 2022-10-20 00:00:00 with difference in each date is 1 month
DatetimeIndex(['2022-10-31', '2022-11-30', '2022-12-31', '2023-01-31',
               '2023-02-28'],
              dtype='datetime64[ns]', freq='M')

Creating list of 5 dates starting from 2022-10-20 00:00:00 with difference in each date is 6 month
DatetimeIndex(['2022-10-31', '2023-04-30', '2023-10-31', '2024-04-30',
               '2024-10-31'],
              dtype='datetime64[ns]', freq='6M')