I would like to choose a random month between the current year and 2016. This is my current, very naive, solution
from random import choice
def get_month():
return choice({'2018-06','2018-05','2018-04','2018-03'})
It's obvious that this set will get too large in the future so what would be a better way of achieving this?
May be you can have two list of month and year since, these will be fixed. Then, you can randomly choose between each and make a date to return. That way I think then no need to generate all different dates and no need to store in large list:
from random import choice
def get_month():
months = list(range(1, 13)) # 12 months list
year = list(range(2016, 2019)) # years list here
val = '{}-{:02d}'.format(choice(year), choice(months))
return val
get_month()
Result:
'2017-05'
Just in case if there is limitation on not exceeding current month if the year selected is current year then, you may need if condition for generating list of months as below:
from random import choice
from datetime import datetime
def get_month():
today = datetime.today() # get current date
year = list(range(2016, today.year+1)) # list till current date year
# randomly select year and create list of month based on year
random_year = choice(year)
# if current year then do not exceed than current month
if random_year == today.year:
months = list(range(1, today.month+1))
else:
# if year is not current year then it is less so can create 12 months list
months = list(range(1, 13))
val = '{}-{:02d}'.format(random_year, choice(months))
return val
You can use the library pandas and use date_range
choice(pd.date_range(start="2016-01-01", end="2018-01-01", freq='M'))
If you want it until today, you can just substitute the startand end arguments for whatever suitable, e.g.
from dateutil.relativedelta import relativedelta
today = datetime.today()
two_years_ago = today - relativedelta(years=2)
choice(pd.date_range(start=two_years_ago, end=today, freq='M'))
I wish my code will give you some inspiration.
import random
import datetime
def RandomMonth(st_year, st_month, ed_year, ed_month):
"""st_year, st_month and ed_year/month is int. """
start_date = datetime.datetime(st_year, st_month, 1)
end_date = datetime.datetime(ed_year, ed_month, 31)
d_days = (end_date - start_date).days
r_days = random.randint(0, ttl_days)
r_date = start_date + datetime.timedelta(days = r_days)
return r_date.strftime("%B/%Y")
You've identified the issue correctly. While the set of discrete items can get unwieldy pretty quickly (actually it won't), selecting a random integer over an arbitrary range is easy.
You should be able to compute the number of months between your dates of interest easily. That means that you have a trivial 1-to-1 mapping from months to integers. Now you can do
m = random.randrange(N)
where N is your total number of months (number of current month + 12 * number of whole years). Mapping back to months is easy using Python's datetime API:
origin = datetime.date(2016, 1, 1)
today = datetime.today()
n = (today.year - origin.year) * 12 + today.month - origin.month
m = random.randrange(n)
x = origin.replace(year=origin.year + m // 12, month=origin.month + m % 12)
Month delta (n) based on this answer and month increment (x) based on this answer. Both computations will become slightly more complicated if you move away from January for the origin.
just pick a random 1-24 then apply some date arithmetic to land on your month from the current date.
from datetime import datetime, date
from dateutil.relativedelta import relativedelta
from random import randint
refdate = date.today() #datetime.now() works too!
for i in range(0,10):
#this will take off at least 1 month and 24 will return 2016-06 from 2018-06
months = randint(1,24)
back = refdate - relativedelta(months=months)
print ("start:%s - %02d months => %s" % (refdate, months, back))
output:
start:2018-06-17 - 24 months => 2016-06-17
start:2018-06-17 - 22 months => 2016-08-17
start:2018-06-17 - 21 months => 2016-09-17
start:2018-06-17 - 08 months => 2017-10-17
start:2018-06-17 - 16 months => 2017-02-17
start:2018-06-17 - 06 months => 2017-12-17
start:2018-06-17 - 07 months => 2017-11-17
start:2018-06-17 - 14 months => 2017-04-17
start:2018-06-17 - 07 months => 2017-11-17
start:2018-06-17 - 07 months => 2017-11-17
you can do them seperately like take random year and take random month, then put it together
def get_month():
year = random.choice([2016, 2017, 2018])
month = random.choice(range(1,13))
new_date = str(year) + "-" + str(month)
return new_date
Try using calendar:
from random import choice
import calendar
def get_month():
l = []
y = 0
for i in range(2016,2019):
l.append(str(i)+'-'+str(calendar.monthrange(i,12)[0]))
return choice(l)
print(get_month())
I think I came with a lighter solution than the one using pandas
current_month = datetime.today().month
current_year = datetime.today().year
start_year = 2016
#total months between now and the start year
total_months = current_month + (current_year - start_year)*12
months = []
month_count = 1
year_count = start_year
#iterate through the list, when it reaches 13, increment year_count and reset the month_count to 1
for month in range(total_months):
if month_count<13:
months.append(str(year_count) + "-" + str("{0:0=2d}".format(month_count)))
month_count+=1
if month_count == 13:
year_count+=1
month_count=1
results
['2016-01', '2016-02', '2016-03', '2016-04', '2016-05', '2016-06', '2016-07', '2016-08', '2016-09', '2016-10', '2016-11', '2016-12', '2017-01', '2017-02', '2017-03', '2017-04', '2017-05', '2017-06', '2017-07', '2017-08', '2017-09','2017-10', '2017-11', '2017-12', '2018-01', '2018-02', '2018-03', '2018-04', '2018-05', '2018-06']
for some reason, when I replace "if month_count == 13" with "else", it only goes up to 2018-04
I would appreciate some feedback on this solution.
