在遍历多个 for 循环时创建字典？

Question

我正在将总统演讲的日期和每个演讲各自的 filename 存储在字典中。 speeches 对象如下所示：

[<a href="/president/obama/speeches/speech-4427">Acceptance Speech at the Democratic National Convention (August 28, 2008)</a>,
<a href="/president/obama/speeches/speech-4424">Remarks on Election Night (November 4, 2008)</a>,...]

而 end_link 看起来像：

['/president/obama/speeches/speech-4427', '/president/obama/speeches/speech-4424',...]

这是我的代码：

date_dict = {}
for speech in speeches:
    text = speech.get_text(strip=True)
    date = text[text.index("(") + 1:text.rindex(")")]
    end_link = [tag.get('href') for tag in speeches if tag.get('href') is not None]
    for x in end_link:
        splitlink = x.split("/")
        president = splitlink[2]
        speech_num = splitlink[4]
        filename = "{0}_{1}".format(president,speech_num)
        if 2 == 2:
            f = date_dict['{0} {1}'.format(filename,date)]

我得到了正确的日期输出（例如 August 15, 1999）并且 filename 没问题。现在，我只是想加入两者并收到以下错误：

date_dict['{0} {1}'.format(filename,date)]
KeyError: 'obama_speech-4427 August 28, 2008'

我真的不知道从这里到哪里去。

Answer 1

您没有将该键的值设置为任何值，因此 Python 认为您正在尝试读取该键。 date_dict 字典为空。

你需要设置一个值，所以像这样：

date_dict[date] = filename

字典有键和值。要分配给字典，您可以这样做：

date_dict['key'] = value

连接部分没有问题。 '{0} {1}'.format(filename,date) 很好，尽管您可能需要下划线而不是 space。如果要在网站上发布，也可能是破折号。

Related question about KeyError

编辑

根据我们的讨论，我认为您需要这样做：

date_dict = {}
for speech in speeches:
    text = speech.get_text(strip=True)
    date = text[text.index("(") + 1:text.rindex(")")]
    end_link = [tag.get('href') for tag in speeches if tag.get('href') is not None]
    for x in end_link:
        splitlink = x.split("/")
        president = splitlink[2]
        speech_num = splitlink[4]
        filename = "{0}_{1}".format(president,speech_num)
        if 2 == 2:
            date_dict[filename] = date

# Prints name date for a given file(just an example)
print("File", filname, "recorded on", date_dict[filename])

在遍历多个 for 循环时创建字典？

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