如何用Pandas的date_range获取从月初开始的周度数据？

Got it, you want to split the date range from 2015-07-01 to 2015-08-01 into weeks that start exactly on July 1st, instead of following pandas' default week boundaries (which is why your initial freq='W' gave you dates starting at 2015-07-05). Besides the timedelta or W-WED methods you already know, here are two simpler, more direct approaches:

方法一：用固定7天间隔freq='7D' #

Since you explicitly want weeks starting on your custom start date, using 7D as the frequency parameter is the most straightforward solution. It generates dates strictly every 7 days starting from your initial date:

import pandas as pd

custom_weekly_range = pd.date_range('2015-07-01', '2015-08-01', freq='7D')
print(custom_weekly_range)

输出结果： #

DatetimeIndex(['2015-07-01', '2015-07-08', '2015-07-15', '2015-07-22', '2015-07-29'],
              dtype='datetime64[ns]', freq='7D')

This perfectly aligns with your requirement—each entry marks the start of a new week, and all dates fall within your target range.

方法二：动态计算周期数生成 #

If you need more flexibility (like adjusting for variable date ranges), you can calculate the number of weeks first, then generate the range using the periods parameter:

import pandas as pd
from datetime import datetime

start_date = datetime(2015, 7, 1)
end_date = datetime(2015, 8, 1)

# Calculate total days and number of full weeks (plus the start day)
total_days = (end_date - start_date).days
num_weeks = total_days // 7 + 1  # +1 to include the starting date itself

custom_weekly_range = pd.date_range(start=start_date, periods=num_weeks, freq='7D')
print(custom_weekly_range)

This gives the exact same output as method one, and it's great for scenarios where your start/end dates might change dynamically.

Bonus: 获取完整周区间 #

If you need the full start-to-end range for each week (not just the start dates), you can easily derive them from the generated DatetimeIndex:

week_intervals = list(zip(custom_weekly_range, custom_weekly_range + pd.Timedelta(days=6)))
for start, end in week_intervals:
    print(f"Week: {start.date()} to {end.date()}")

输出： #

Week: 2015-07-01 to 2015-07-07
Week: 2015-07-08 to 2015-07-14
Week: 2015-07-15 to 2015-07-21
Week: 2015-07-22 to 2015-07-28
Week: 2015-07-29 to 2015-08-04

Note that the last week's end date goes beyond your original 2015-08-01—you can truncate it manually if needed.

内容的提问来源于stack exchange，提问作者lu5er