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
# Python3 code to demonstrate working of# Random K dates in Range# Using choices() + timedelta() + loopfrom datetime import date, timedeltafrom random import choices# initializing dates rangestest_date1, test_date2 = date(2015, 6, 3), date(2015, 7, 1)# printing datesprint("The original range : " + str(test_date1) + " " + str(test_date2))# initializing KK = 7res_dates = [test_date1]# loop to get each date till end datewhile test_date1 != test_date2: test_date1 += timedelta(days=1) res_dates.append(test_date1)# random K dates from packres = choices(res_dates, k=K)# printingprint("K random dates in range : " + str(res)) |
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
# Python3 code to demonstrate working of# Random K dates in Range# Using randrange() + timedelta() + loopfrom datetime import date, timedeltaimport random# initializing dates rangestest_date1, test_date2 = date(2015, 6, 3), date(2015, 7, 1)# printing datesprint("The original range : " + str(test_date1) + " " + str(test_date2))# initializing KK = 7# getting days between datesdates_bet = test_date2 - test_date1total_days = dates_bet.daysres = []for idx in range(K): random.seed(a=None) # getting random days randay = random.randrange(total_days) # getting random dates res.append(test_date1 + timedelta(days=randay))# printingprint("K random dates in range : " + str(res)) |
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, timedeltaimport numpy as np# initializing dates rangestest_date1, test_date2 = date(2015, 6, 3), date(2015, 7, 1)# printing datesprint("The original range : " + str(test_date1) + " " + str(test_date2))# initializing KK = 7# getting days between datesdates_bet = test_date2 - test_date1total_days = dates_bet.days# create an array of total days and select K random values without replacementrandays = np.random.choice(total_days, K, replace=False)# getting random datesres = [test_date1 + timedelta(days=int(day)) for day in randays]# printingprint("K random dates in range : " + str(res)) |
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)
