我正在编写一个 for 循环，从 pytrends 包中获取 Google Trends。现在我希望 for 循环为它在关键字列表中找到的每个关键字创建一个数据框。但我希望数据帧以列表项的编号而不是列表中的实际字符串命名。现在这是我的代码：from pytrends.request import TrendReqpytrend = TrendReq(hl='de', tz=390, retries=10, backoff_factor=0.5)keywords = ['foo', 'bar', 'dummy']for keyword in keywords:  try:    pytrend.build_payload(      kw_list=[keyword],      geo='DE',      timeframe = 'now 1-d')    gbl = globals()    gbl['df_'+[str(i) for i in range(len(keywords))]] = pytrend.interest_over_time()    gbl['df_'+[str(i) for i in range(len(keywords))]] = gbl['df_'+[str(i) for i in range(len(keywords))]].drop(labels=['isPartial'],axis='columns')    print(keyword + ' was succesfully pulled from Google Trends')  except Exception as e:    print(keyword + ' was not successfully pulled because of the following error: ' + str(e))    continue但不幸的是这给了我以下错误：foo was not successfully pulled because of the following error: can only concatenate str (not "list") to strbar was not successfully pulled because of the following error: can only concatenate str (not "list") to strdummy was not successfully pulled because of the following error: can only concatenate str (not "list") to str所以，我的问题是，如何获取列表中的项目编号来创建df_0、df_1、df_2等？谢谢！