finding first day of the month in python

Question

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?

Asked By: tkyass

||

Source

Answer 1

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)

Answered By: lampslave

Answer 2

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

Answered By: mba12

Answer 3

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.

Answered By: andrew

Answer 4

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

Answered By: Bill Bell

Answer 5

Can be done on the same line using date.replace:

from datetime import datetime

datetime.today().replace(day=1)

Answered By: Gustavo Eduardo Belduma

Answer 6

Use arrow.

import arrow
arrow.utcnow().span('month')[0]

Answered By: ImPerat0R_

Answer 7

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)

Answered By: dtatarkin

Answer 8

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)

Answered By: Balaji.J.B

Answer 9

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

Answered By: mhyousefi

Answer 10

This could be an alternative to Gustavo Eduardo Belduma’s answer:

import datetime 
first_day_of_the_month = datetime.date.today().replace(day=1)

Answered By: tjurkan

Answer 11

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))

Answered By: Fernando Zuniga

Answer 12

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)

Answered By: Rich

Answer 13

One-liner:

from datetime import datetime, timedelta
last_month=(datetime.now().replace(day=1) - timedelta(days=1)).replace(day=1)

Answered By: Jouberto Fonseca

Answer 14

Inspired by Jouberto’s and @akx‘s answers (elsewhere), oneliners without any dependencies:

now = datetime.datetime.now(tz=ZoneInfo("UTC"))
this_month = now.replace(day=1, hour=0, minute=0, second=0, microsecond=0)
next_month = (this_month.replace(day=28) + datetime.timedelta(days=4)).replace(day=1)
last_month = (this_month.replace(day=1) - datetime.timedelta(days=1)).replace(day=1)

Answered By: Aapo Rista

finding first day of the month in python

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