Week from date python

Get Week Number from Date in Python

To get the week number from a date or datetime object in Python, the easiest way is to use the Python isocalendar() function.

import datetime print(datetime.date(2022, 6, 20).isocalendar()[1]) #Output: 25

The Python datetime strftime() function also can be helpful to get the week number from the date in Python, depending on which calendar you want to use.

import datetime dt = datetime.date(2022, 1, 2) #Date is January 2nd (Sunday), 2022, year starts with Saturday print(dt.strftime("%W")) print(dt.strftime("%U")) print(dt.strftime("%V")) #Output: '00'; Monday is considered first day of week, Sunday is the last day of the week which started in the previous year '01'; Sunday is considered first day of week '52'; ISO week number; result is '52' since there is no Thursday in this year's part of the week

When working with date and datetime variables in Python, the ability to easily be able to get different pieces of information about the dates is valuable.

One such piece of information is the week of the year.

There are a few different ways to get the week number of the year in Python.

The easiest way to get the week number is to use the Python datetime isocalendar() function.

The isocalendar() function returns a tuple object with three components: year, week and weekday.

The ISO calendar is a widely used variant of the Gregorian calendar.

The ISO year consists of 52 or 53 full weeks, and where a week starts on a Monday and ends on a Sunday. The first week of an ISO year is the first (Gregorian) calendar week of a year containing a Thursday. This is called week number 1, and the ISO year of that Thursday is the same as its Gregorian year.

Below is an example of how you can get the week number from a date using Python.

import datetime print(datetime.date(2022, 6, 20).isocalendar()[1]) #Output: 25

If you are using Python 3.9+, then you can access the ‘week’ attribute from isocalendar().

import datetime print(datetime.date(2022, 6, 20).isocalendar().week) #Output: 25

Using strftime() to Get Week Number from Date in Python

Another way you can get the week number from a date variable in Python is with the strftime() function.

The strftime() function allows you to format dates with different date formats.

You can pass “%W”, “%U”, or “%V” to strftime() to get the number of the week according to three different calendars.

“%W” corresponds to the calendar where Monday is considered the first day of the week.

“%U” corresponds to the calendar where Sunday is considered the first day of the week.

“%V” corresponds to the ISO calendar.

Below is an example of how you can use strftime() to get the week number from a date in Python.

import datetime print(datetime.date(2022, 6, 20).strftime("%W")) # Monday is considered first day of week print(datetime.date(2022, 6, 20).strftime("%U")) # Sunday is considered first day of week print(datetime.date(2022, 6, 20).strftime("%V")) # ISO week number #Output: 25 25 25

Considering Calendar Differences When Finding Week Number in Python

Depending on which day of the week your calendar starts on, the week number can change depending on the date. For example, the first week of January can cause troubles for developers if they aren’t careful.

With the strftime() function, you can return the week number based on the three calendars we described above.

Depending on which calendar you are using, there can be differences of which week number you will get for certain dates.

Below shows the difference between the Gregorian calendar and ISO calendar return values for the first Sunday of the year.

import datetime dt = datetime.date(2022, 1, 2) #Date is January 2nd (Sunday), 2022, year starts with Saturday print(dt.strftime("%W")) # Monday is considered first day of week, Sunday is the last day of the week which started in the previous year print(dt.strftime("%U")) # Sunday is considered first day of week print(dt.strftime("%V")) # ISO week number; result is '52' since there is no Thursday in this year's part of the week #Output: 00 01 52

Hopefully this article has been useful for you to use Python to get the week number from a date.

Other Articles You’ll Also Like:

• 1. Perform Reverse Dictionary Lookup in Python
• 2. Python power function – Exponentiate Numbers with math.pow()
• 3. Factorial Program in Python Using For Loop and While Loop
• 4. Using Python to Check If a Number is a Perfect Square
• 5. Python issuperset() Function – Check if Set is Superset of Another Set
• 6. Creating a Random Color Turtle in Python
• 7. How to Clear Turtle Screen in Python with clear() Function
• 8. Get First Key and Value in Dictionary with Python
• 9. Python Split List into N Sublists
• 10. pandas ewm – Calculate Exponentially Weighted Statistics in DataFrame

About The Programming Expert

The Programming Expert is a compilation of a programmer’s findings in the world of software development, website creation, and automation of processes.

Programming allows us to create amazing applications which make our work more efficient, repeatable and accurate.

At the end of the day, we want to be able to just push a button and let the code do it’s magic.

You can read more about us on our about page.

Источник

Extract week number from date in Pandas Python

dt.Week is the inbuilt method for finding the week number from date in Pandas Python. There is another method to find the week number of the year from date in pandas using strftime() function Let’s see how to

• Extract the week number from date in python using dt.week
• Get week number from date using strftime() function

First lets create the dataframe

import pandas as pd import numpy as np import datetime date1 = pd.Series(pd.date_range('2012-1-1 12:00:00', periods=7, freq='M')) df = pd.DataFrame(dict(date_given=date1)) print(df)

so the resultant dataframe will be

Get the week number from date in pandas python using dt.week:

Week function gets week number from date. Ranging from 1 to 52 weeks

df['week_number_of_year'] = df['date_given'].dt.week df

so the resultant dataframe will be

Get week number from date using strftime() function:

strftime() function gets week number from date. Ranging from 1 to 52 weeks

df['week_number_of_year'] = df['date_given'].dt.strftime('%U') df

‘%U’ represents the week number of the year (Sunday as the first day of the week) as a zero padded decimal number. All days in a new year preceding the first Sunday are considered to be in week 0. so the resultant dataframe will be,

Author

With close to 10 years on Experience in data science and machine learning Have extensively worked on programming languages like R, Python (Pandas), SAS, Pyspark. View all posts

Related Posts:

Источник