在 Python 中执行延迟执行并获取异常默认值

Question

我正在解析 HTML 并且文件中有很多可选属性，如果在我读取它们时出现异常，我会改用一些默认值。有什么方法可以准备一个通用函数来尝试检索属性并在异常 return 时检索默认值？目前，我有这样的东西，但是非常难看。

        try:
            title = soup.find('h1').text
        except:
            title = "b/d"
        try:
            location = soup.find('a', attrs={'href': '#map'}).text
        except:
            location = "none"
        try:
            downside= soup.find('strong', attrs={'aria-label': 'downside'}).text
        except:
            downside = "0"
        try:
            incremental = soup.find('div', attrs={'aria-label': 'incremental'}).contents[3].text
        except:
            incremental = "1"
        try:
            difference = soup.find('div', attrs={'aria-label': 'difference'}).contents[1].text
        except:
            difference = "2"
        try:
            part = soup.find('div', attrs={'aria-label': 'part'}).contents[1].text
        except:
            part = "3"

Answer 1

不要捕获裸异常。

实现泛型函数的一种直接方法是

def get_attribute_text(soup, element, attrs, default_value, contents_index=None):
    try:
        if contents_index:
            return soup.find(element, attrs=attrs).contents[contents_index].text
        return soup.find(element, attrs=attrs).text
    except AttributeError:
        return default_value

并像这样使用：

title = get_attribute_text(soup, 'h1', {}, 'b/d')
location = get_attribute_text(soup, 'a', {'href': '#map'}, 'none')
...
incremental = get_attribute_text(soup, 'div', {'aria-label': 'incremental'}, '1', 3)
...

在 Python 中执行延迟执行并获取异常默认值

Do lazy execution and get default value on exception in Python

python

default

exception