finding first day of the month in python
PythonDatetimePython Problem Overview
I'm trying to find the first day of the month in python with one condition: if my current date passed the 25th of the month, then the first date variable will hold the first date of the next month instead of the current month. I'm doing the following:
import datetime
todayDate = datetime.date.today()
if (todayDate - todayDate.replace(day=1)).days > 25:
x= todayDate + datetime.timedelta(30)
x.replace(day=1)
print x
else:
print todayDate.replace(day=1)
is there a cleaner way for doing this?
Python Solutions
Solution 1 - Python
Can be done on the same line using date.replace:
from datetime import datetime
datetime.today().replace(day=1)
Solution 2 - Python
This is a pithy solution.
import datetime
todayDate = datetime.date.today()
if todayDate.day > 25:
todayDate += datetime.timedelta(7)
print todayDate.replace(day=1)
One thing to note with the original code example is that using timedelta(30) will cause trouble if you are testing the last day of January. That is why I am using a 7-day delta.
Solution 3 - Python
Use dateutil.
from datetime import date
from dateutil.relativedelta import relativedelta
today = date.today()
first_day = today.replace(day=1)
if today.day > 25:
print(first_day + relativedelta(months=1))
else:
print(first_day)
Solution 4 - Python
from datetime import datetime
date_today = datetime.now()
month_first_day = date_today.replace(day=1, hour=0, minute=0, second=0, microsecond=0)
print(month_first_day)
Solution 5 - Python
Use arrow.
import arrow
arrow.utcnow().span('month')[0]
Solution 6 - Python
This could be an alternative to Gustavo Eduardo Belduma's answer:
import datetime
first_day_of_the_month = datetime.date.today().replace(day=1)
Solution 7 - Python
Yes, first set a datetime to the start of the current month.
Second test if current date day > 25 and get a true/false on that. If True then add add one month to the start of month datetime object. If false then use the datetime object with the value set to the beginning of the month.
import datetime
from dateutil.relativedelta import relativedelta
todayDate = datetime.date.today()
resultDate = todayDate.replace(day=1)
if ((todayDate - resultDate).days > 25):
resultDate = resultDate + relativedelta(months=1)
print resultDate
Solution 8 - Python
The arrow module will steer you around and away from subtle mistakes, and it's easier to use that older products.
import arrow
def cleanWay(oneDate):
if currentDate.date().day > 25:
return currentDate.replace(months=+1,day=1)
else:
return currentDate.replace(day=1)
currentDate = arrow.get('25-Feb-2017', 'DD-MMM-YYYY')
print (currentDate.format('DD-MMM-YYYY'), cleanWay(currentDate).format('DD-MMM-YYYY'))
currentDate = arrow.get('28-Feb-2017', 'DD-MMM-YYYY')
print (currentDate.format('DD-MMM-YYYY'), cleanWay(currentDate).format('DD-MMM-YYYY'))
In this case there is no need for you to consider the varying lengths of months, for instance. Here's the output from this script.
25-Feb-2017 01-Feb-2017
28-Feb-2017 01-Mar-2017
Solution 9 - Python
I found a clean way to do this is to create a datetime object using the month and year attributes of todayDate, with days set to 1 i.e.
import datetime
todayDate = datetime.date.today()
firstOfMon = datetime.date(todayDate.year, todayDate.month, 1)
Solution 10 - Python
You can use dateutil.rrule:
In [1]: from dateutil.rrule import *
In [2]: rrule(DAILY, bymonthday=1)[0].date()
Out[2]: datetime.date(2018, 10, 1)
In [3]: rrule(DAILY, bymonthday=1)[1].date()
Out[3]: datetime.date(2018, 11, 1)
Solution 11 - Python
My solution to find the first and last day of the current month:
def find_current_month_last_day(today: datetime) -> datetime:
if today.month == 2:
return today.replace(day=28)
if today.month in [4, 6, 9, 11]:
return today.replace(day=30)
return today.replace(day=31)
def current_month_first_and_last_days() -> tuple:
today = datetime.now().replace(hour=0, minute=0, second=0, microsecond=0)
first_date = today.replace(day=1)
last_date = find_current_month_last_day(today)
return first_date, last_date
Solution 12 - Python
First day of next month:
from datetime import datetime
class SomeClassName(models.Model):
if datetime.now().month == 12:
new_start_month = 1
else:
new_start_month = datetime.now().month + 1
Then we replace the month and the day
start_date = models.DateField(default=datetime.today().replace(month=new_start_month, day=1, hour=0, minute=0, second=0, microsecond=0))
Solution 13 - Python
One-liner:
from datetime import datetime, timedelta
last_month=(datetime.now().replace(day=1) - timedelta(days=1)).replace(day=1)