使用 "minus x days" 和 Python 3.8 的语法？

Question

    import pandas as pd
    import requests
    from bs4 import BeautifulSoup
    import time
    import datetime
    from datetime import date, timedelta

    # MM/DD/YYYY : time.strftime("%m/%d/%Y")
    # YYYYMMDD : time.strftime('%Y%m%d')

if datetime.datetime.now().isoweekday() == 1 : # If today is a Monday -> some dates must be minus 3 days to take the previous Friday's data

    url_DAX = 'https://www.eurexchange.com/exchange-en/market-data/statistics/market-statistics-online/100!onlineStats?viewType=4&productGroupId=13394&productId=34642&cp=&month=&year=&busDate=' + str(time.strftime('%Y%m%d') - timedelta(days=3))   #Should be minus 3 days
    df = pd.read_html(url_DAX)[0]
    df.to_csv('results_DAX_' + str(time.strftime('%Y%m%d')) + '.csv') 
    print(df)

这给我以下错误：

 url_DAX = 'https://www.eurexchange.com/exchange-en/market-data/statistics/market-statistics-online/100!onlineStats?viewType=4&productGroupId=13394&productId=34642&cp=&month=&year=&busDate=' + str(time.strftime('%Y%m%d') - timedelta(days=2))  # Should be minus 2 days
TypeError: unsupported operand type(s) for -: 'str' and 'datetime.timedelta'

我想知道如何正确书写，因为我需要以下格式的最终日期（减去 1、2 或 3 天之后）：YYYYMMDD。

谢谢

Answer 1

您可以使用 datetime 模块。制作日期时间实例，然后添加您想要的时间增量：

dtm += datetime.timedelta(hours=2)

Answer 2

在单独的语句中做减法：

from datetime import date, timedelta
dt = date.today() - timedelta(days=2)

然后将其转换为您格式的字符串

busdate =  dt.strftime('%Y%m%d')
url_DAX = 'https://www.eurexchange.com/exchange-en/market-data/statistics/market-statistics-online/100!onlineStats?viewType=4&............&busDate=' + busdate

使用 "minus x days" 和 Python 3.8 的语法？

Syntax to use to make "minus x days" with Python 3.8?

python

python-3.x

python-datetime