How to Generate a Random Date Between Two Dates in Python?

Problem Formulation and Solution Overview

This article will show you how to generate a random date between two dates in Python.

💬 Question: How would we write code to generate a random date between two dates?

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We can accomplish this task by one of the following options:

• Method 1: Use datetime.timedelta() and random.random()
• Method 2: Use datetime.timedelta() and random.randint()
• Method 3: Use datetime.datetime.combine() and random.random()
• Method 4: Use date_range() and sample()

Preparation

Examples 1-3 in this article require the datetime and random libraries to run error-free.

In this regard, add these lines to the top of these snippets.

import datetime
from datetime import timedelta
import random

Method 1: Use timedelta and random()

This example uses datetime.timedelta() and random.random() to generate an arbitrary date between two dates.

start_date = datetime.datetime.now()
end_date = start_date + timedelta(days=10)

random_date = start_date + (end_date - start_date) * random.random()
print(random_date)

The first line calls the datetime.datetime.now() function, which generates the current datetime. The results save to start_date.

The following line calculates the end_date by adding 10 days to the start_date (timedelta(days=10). The results save to end_date.

On the next line, the number of days between the start_date and end_date is calculated (end_date - start_date), resulting, in this case, to 10. A random number is generated by multiplying this value by random.random().

This number is added to the start_date (days), saved as random_date, and output to the terminal.

Method 2: Use timedelta() and randint()

This example uses datetime.timedelta() and random.randint() to generate an arbitrary date between two dates.

start_date = datetime.date(2022, 10, 1)
end_date   = datetime.date(2022, 11, 30)

num_days   = (end_date - start_date).days
rand_days   = random.randint(1, num_days)
random_date = start_date + datetime.timedelta(days=rand_days)
print(random_date)

This code’s first two (2) lines declare two (2) dates by calling the datetime.date() function and passing in the requisite: year, month, and day arguments. These save to start_date and end_date, respectively.

The following line calculates the number of days between the start_date and end_date. The results save to num_days.

On the next line, the random.randint() function is called and passed two (2) arguments, a start position (1) and a stop position (num_days). This returns a random integer and saves it to rand_days.

Then, a random date is calculated by calling passing the above generated random number (rand_days) to datetime.timedelta() and adding said number to the start_date.

The results save to random_date and are output to the terminal. In this case, the random number 41 (days) was added to random_date.

Method 3: Use combine() and random()

This example uses datetime.datetime.combine() and random.random() to generate an arbitrary date between two dates.

start_date = datetime.date(2022, 10, 1)
end_date = datetime.date(2022, 10, 10)

random_date = start + (end - start) * random.random()
random_date = datetime.datetime.combine(random_date, datetime.datetime.min.time())
print(random_date)

The code’s first two (2) lines declare two (2) dates by calling the datetime.date() function and passing in the requisite: year, month, and day arguments. These save to start_date and end_date, respectively.

Next, the number of days between the start_date and end_date is calculated, and a random number is generated from this.

The following line calls the datetime.datetime.combine() function and passes it two arguments, random_date, and datetime.datetime.min.time() to generate a random date and append a default time format to the output. The results save to random_date and output to the terminal.

Method 4: Use date_range() and sample()

This example uses date_range() and sample() to generate five (5) arbitrary dates between two dates.

import pandas as pd 

def generate_dates(start, end, n, seed=1, replace=False):
    dates = pd.date_range(start, end).to_series()
    return dates.sample(n, replace=replace, random_state=seed)

print(generate_dates('20221001', '20221010', 5, seed=1))

The above code imports the pandas library, allowing access to and manipulating of the data.

The following lines declare a function generate_dates, and passes it the following:

• start: a start date formatted as ‘20220101’.
• end: an end date formatted as ‘20220331’
• seed: the total number of dates to generate
• replace=False: allow (True) or disallow (False) sampling of the same row more than once.

Inside this function, the start and end dates are determined and converted to a Series (to_series()). In, this case 10 dates are generated from the start_date to the end_date inclusive.

Five (5) random dates are retrieved from the above and returned when the function is called on the following line. The result is as follows.

Summary

This article has provided four (4) ways to generate a random date between two dates to select the best fit for your coding requirements.

Good Luck & Happy Coding!

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