Six Ways to Get the Weekday of a Specific Date in Python

When performing data analysis in Python, grouping by date often requires knowing the weekday of a specific date. Using the example date 2022‑02‑22, this article presents six methods to obtain the weekday.

datetime.weekday()

The built‑in datetime module provides the weekday() method, which returns an integer from 0 (Monday) to 6 (Sunday). Example:

from datetime import datetime
datetime.date(2022, 2, 22).weekday()
# Output: 1

To map the integer to a Chinese weekday name, define a list and index it:

week_list = ["星期一","星期二","星期三","星期四","星期五","星期六","星期日"]
week_list[datetime.date(2022, 2, 22).weekday()]
# Output: '星期二'

datetime.isoweekday()

The isoweekday() method works similarly but returns 1 (Monday) to 7 (Sunday):

import datetime
datetime.date(2022, 2, 22).isoweekday()
# Output: 2

datetime.strftime()

Use strftime() to format a date as a string. The format code %A yields the full English weekday name, while %a gives the abbreviated name:

import datetime
datetime.date(2022, 2, 22).strftime("%A")
# Output: 'Tuesday'

datetime.date(2022, 2, 22).strftime("%a")
# Output: 'Tue'

calendar module

The standard calendar module also offers weekday() and day_name for weekday lookup:

import calendar
calendar.weekday(2022, 2, 22)
# Output: 1

date_week = datetime.date(2022, 2, 22).weekday()
calendar.day_name[date_week]
# Output: 'Tuesday'

pendulum library

For more advanced date handling, the third‑party pendulum library can be used. Its day_of_week attribute returns the ISO weekday number:

import pendulum
pendulum.parse('2022-02-22').day_of_week
# Output: 2

Pandas

When working with tabular data, Pandas provides convenient accessors. The Series.dt.day_name() method returns the weekday name for each datetime entry:

import pandas as pd
from datetime import datetime

df = pd.DataFrame({
    "name": ["张三", "李四", "朱五"],
    "date": [datetime(2022, 2, 21), datetime(2022, 2, 22), datetime(2022, 2, 23)]
})

df["week_name"] = df["date"].dt.day_name()
print(df)
# Shows the weekday names for each row

By covering these six approaches— datetime.weekday() , datetime.isoweekday() , datetime.strftime() , calendar , pendulum , and Pandas —the article equips readers with multiple tools to retrieve weekday information in Python for data analysis tasks.