我要异常处理'列表索引超出范围'。 [英] I want to exception handle 'list index out of range.'

问题描述

我正在使用 BeautifulSoup 并解析一些HTML。

I am using BeautifulSoup and parsing some HTMLs.

我从每个HTML 获取某些数据（用于循环），并将该数据添加到某个列表。

I'm getting a certain data from each HTML (using for loop) and adding that data to a certain list.

问题是，一些HTML具有不同的格式（而且它们不拥有我想要的数据）

The problem is, some of the HTMLs have different format (and they don't have the data that I want in them).

所以，我试图使用异常处理和添加值 null 到列表（我应该这样做，因为数据序列很重要。）

So, I was trying to use exception handling and add value null to the list (I should do this since the sequence of data is important.)

例如，我有一个代码如：

For instance, I have a code like:

soup = BeautifulSoup(links)
dlist = soup.findAll('dd', 'title')
# I'm trying to find content between <dd class='title'> and </dd>
gotdata = dlist[1]
# and what i want is the 2nd content of those
newlist.append(gotdata)
# and I add that to a newlist

，其中一些链接没有任何< dd class ='title' < / code>，所以我想做的是将字符串 null 添加到列表中。

and some of the links don't have any <dd class='title'>, so what I want to do is add string null to the list instead.

出现错误：

list index out of range.

我所做的尝试是添加一些这样的行：

What I have done tried is to add some lines like this:

if not dlist[1]:  
   newlist.append('null')
   continue

但是没有办法。仍然显示错误：

But it doesn't work out. It still shows error:

list index out of range.

我该怎么办？我应该使用异常处理吗？还是有更简单的方法？

What should I do about this? Should I use exception handling? or is there any easier way?

任何建议？任何帮助将是非常好的！

Any suggestions? Any help would be really great!

推荐答案

处理异常是要走的路：

try:
    gotdata = dlist[1]
except IndexError:
    gotdata = 'null'

当然你也可以检查 len（） DLIST ;但处理异常更直观。

Of course you could also check the len() of dlist; but handling the exception is more intuitive.

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