Beautiful Soup 4 .string()'NoneType'对象不可调用 [英] Beautiful Soup 4 .string() 'NoneType' object is not callable

问题描述

from bs4 import BeautifulSoup
import sys

soup = BeautifulSoup(open(sys.argv[2]), 'html.parser')
print(soup.prettify)

if sys.argv[1] == "h":
    h2s = soup.find_all("h2")
    for h in h2s:
        print(h.string())

第一个打印语句(作为测试添加)有效-所以我知道BS4正常工作.第二条打印语句将引发:

The first print statement (added as a test) works - so I know BS4 is working and everything. The second print statement throws:

File "sp2gd.py", line 40, in <module>
    print(h.string())
TypeError: 'NoneType' object is not callable

推荐答案

BeautifulSoup的 .string 是一个属性，不是可调用的方法，并且当元素的内容没有单个，明确的字符串表示形式时(例如，当它包含多个子元素时)，它的值是 None -因此出现错误消息.

BeautifulSoup's .string is a property, not a callable method, and when there's no single, unambiguous string representation of the contents of the element (for instance, when it contains multiple child elements), its value is None – hence the error message.

将括号()放在 h.string 之后，您将停止出错:

Lose the parentheses () after h.string and you'll stop getting errors:

if sys.argv[1] == "h":
    h2s = soup.find_all("h2")
    for h in h2s:
        print(h.string)  # no parentheses

...尽管如果 h2 元素有多个子代，则结果可能不会特别有启发性.在这种情况下， .strings 和 .stripped_strings 派上用场:

... although if the h2 elements have multiple children, the results might not be especially illuminating. In that case, .strings and .stripped_strings come in handy:

if sys.argv[1] == "h":
    h2s = soup.find_all("h2")
    for h in h2s:
        for s in h.stripped_strings:
            print(s)

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