Python – Generate k random dates between two other dates
Given two dates, the task is to write a Python program to get K dates randomly.
Input : test_date1, test_date2 = date(2015, 6, 3), date(2015, 7, 1), K = 7
Output : [datetime.date(2015, 6, 18), datetime.date(2015, 6, 25), datetime.date(2015, 6, 29), datetime.date(2015, 6, 11), datetime.date(2015, 6, 11), datetime.date(2015, 6, 10), datetime.date(2015, 6, 24)]
Explanation : 7 random dates starting from 3 June 2015 to 1 July 2015 are generated.
Input : test_date1, test_date2 = date(2015, 6, 3), date(2015, 8, 1), K = 6
Output : [datetime.date(2015, 6, 20), datetime.date(2015, 7, 22), datetime.date(2015, 6, 29), datetime.date(2015, 6, 18), datetime.date(2015, 6, 13), datetime.date(2015, 7, 14)]
Explanation : 6 random dates starting from 3 June 2015 to 1 August 2015 are generated.
Method #1 : Using choices() + loop + timedelta()
In this, we extract all dates in range using loop and timedelta() of 1-day difference. Among them K random dates are chosen using choices().
Python3
from datetime import date, timedelta
from random import choices
test_date1, test_date2 = date( 2015 , 6 , 3 ), date( 2015 , 7 , 1 )
print ( "The original range : " + str (test_date1) + " " + str (test_date2))
K = 7
res_dates = [test_date1]
while test_date1 ! = test_date2:
test_date1 + = timedelta(days = 1 )
res_dates.append(test_date1)
res = choices(res_dates, k = K)
print ( "K random dates in range : " + str (res))
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Output:
The original range : 2015-06-03 2015-07-01
K random dates in range : [datetime.date(2015, 6, 25), datetime.date(2015, 6, 10), datetime.date(2015, 6, 18), datetime.date(2015, 6, 7), datetime.date(2015, 6, 4), datetime.date(2015, 6, 16), datetime.date(2015, 6, 12)]
Time complexity : O(n + klogn)
Space complexity : O(n + k)
Method #2 : Using randrange() + timedelta() + loop
In this, a total number of days between ranges is extracted and that range is used to get elements K times, adding a random index number from start date extracted using randrange().
Python3
from datetime import date, timedelta
import random
test_date1, test_date2 = date( 2015 , 6 , 3 ), date( 2015 , 7 , 1 )
print ( "The original range : " + str (test_date1) + " " + str (test_date2))
K = 7
dates_bet = test_date2 - test_date1
total_days = dates_bet.days
res = []
for idx in range (K):
random.seed(a = None )
randay = random.randrange(total_days)
res.append(test_date1 + timedelta(days = randay))
print ( "K random dates in range : " + str (res))
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Output:
The original range : 2015-06-03 2015-07-01
K random dates in range : [datetime.date(2015, 6, 26), datetime.date(2015, 6, 5), datetime.date(2015, 6, 6), datetime.date(2015, 6, 18), datetime.date(2015, 6, 21), datetime.date(2015, 6, 15), datetime.date(2015, 6, 12)]
Time complexity : O(k)
Space Complexity : O(k)
Method #3: Using numpy.random.choice() + timedelta()
step-by-step breakdown of the program:
- Import the required modules – datetime and numpy.
- Define the starting and ending dates of the date range, test_date1 and test_date2, respectively, using the date() function from the datetime module.
- Print the original date range using the print() function and string formatting.
- Initialize the value of K, the number of random dates to generate.
- Calculate the number of days between the two dates using the timedelta() function from the datetime module.
- Convert the total_days object to an integer value using the days attribute.
- Use the numpy.random.choice() function to generate an array of K unique random integers from 0 to total_days-1 without replacement.
- Iterate over the randays array and convert each element to an integer value using the int() function.
- Use the timedelta() function to calculate the date corresponding to each random day in the date range.
- Append each resulting date to a list called res.
- Print the list of K random dates using the print() function and string formatting.
Python3
from datetime import date, timedelta
import numpy as np
test_date1, test_date2 = date( 2015 , 6 , 3 ), date( 2015 , 7 , 1 )
print ( "The original range : " + str (test_date1) + " " + str (test_date2))
K = 7
dates_bet = test_date2 - test_date1
total_days = dates_bet.days
randays = np.random.choice(total_days, K, replace = False )
res = [test_date1 + timedelta(days = int (day)) for day in randays]
print ( "K random dates in range : " + str (res))
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OUTPUT :
The original range : 2015-06-03 2015-07-01
K random dates in range : [datetime.date(2015, 6, 7), datetime.date(2015, 6, 13), datetime.date(2015, 6, 25), datetime.date(2015, 6, 10), datetime.date(2015, 6, 8), datetime.date(2015, 6, 22), datetime.date(2015, 6, 28)]
Time complexity: O(K)
Auxiliary space: O(K)
Last Updated :
21 Apr, 2023
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