如何使用列表(datetime.timedelta)中的循环特定日期并提取到不同的csv文件

以下代码不正确,因为datetime.timedelta(day=)必须包含整数而不是字符串。

从链接中获取引用 How to use for loop and add one day (timedelta) every time

在这种情况下很难定义新的函数,有什么简单方便的方法可以解决吗?

--已解决--通过添加:day=int(字符串格式的day)

def get_data():

    # Every stock can loop on every periods
    stocks = ['A', 'B', 'C', 'D', 'E','F','G','H']

    # since the limitation of API data provider, ~180 days' data can be extracted per request 
    periods = ['0','178','356','534']

    for x in stocks:

        for _ in range(10):
            tws.reqHistoricalData(x)

            for n in periods:

                data = pd.DataFrame(reqHistoricalData(datetime.datetime.today()- datetime.timedelta(days=n)).strftime("%Y%m%d %H:%M:%S %Z"))

                # if there are any empty data, it can "smart" loop back and start from corresponding stock AND period without running again from the beginning
                if not data.empty:
                    #1 st Edited
                    data.to_csv("filename"+x+"@"+n+".csv")
                    break

                print("Data is empty")

现有代码仅导出与FielNeMa@ 0、FielNeMeb @ 0、FieleCeC @ 0的CVS… 但是,它不能导出到不同的csv文件,如下所示

data.to_csv("filename"+x+"@"+n+".csv")

filenameA@0.csv
filenameA@178.csv 
filenameA@356.csv
filenameA@534.csv
filenameB@0.csv
filenameB@178.csv
filenameB@356.csv
filenameB@534.csv
filenameC@0.csv
..........