Question

这是我的html：

<html>
<body>
<h2>Pizza</h2>
<p>This is some random paragraph without child tags.</p>
<p>Delicious homebaked pizza.<br><em></em>$8.99 pp</em></p>
<h2>Eggplant Parmesan</h2>
<p>Try the authentic <i>Italian flavor</i> of baked aubergine.<br><em>$6.99 pp</em></p>
<h2>Italian Ice Cream</h2>
<p>Our dessert specialty.<br><em>$3.99 pp</em></p>
</body>
</html>

使用BeautifulSoup，我要获取h2和p标签显示的文本，将其替换为树中的前缀版本，并在屏幕上打印出来。对于h2标签，这可以正常工作：

from bs4 import BeautifulSoup

with open("/var/www/html/Test/index.html", "r") as f:
 soup = BeautifulSoup(f, "lxml")

f = open("/var/www/html/Test/I18N_index.html", "w+")

for h2 in soup.find_all('h2'):
    i18n_string = "I18N_"+h2.string
    h2.string.replace_with(i18n_string)
    print(h2.string)

f.write(str(soup))


###Output:##############################################
# $ python ./test.py
# I18N_Pizza
# I18N_Eggplant Parmesan
# I18N_Italian Ice Cream
########################################################

在我的I18N_index.html中，所有3个字符串都正确地以'I18N_'为前缀。

但是，我的p标签包含子标签，对于这些标签，返回类型为'None'。结果，串联不再起作用：

    for p in soup.find_all('p'):
        i18n_string = "I18N_"+p.string
        p.string.replace_with(i18n_string)
        print(p.string)

    f.write(str(soup))

###Output:##################################################
# $ python ./test.py
# I18N_Pizza
# I18N_Eggplant Parmesan
# I18N_Italian Ice Cream
# I18N_This is some random paragraph without child tags.
# Traceback (most recent call last):
  # File "./test.py", line 15, in <module>
    # i18n_string = "I18N_"+p.string
# TypeError: cannot concatenate 'str' and 'NoneType' objects
############################################################

我从this thread了解了join函数。让我进行串联并在屏幕上打印出结果字符串，而不是汤树中的替换字符串：

for p in soup.find_all('p'):
    joined = ''.join(p.strings)
    i18n_string = "I18N_"+joined
    #joined.replace_with(i18n_string)
    print (i18n_string)

###Output with 'joined.replace_with(i18n_string)' DISABLED:###
# I18N_Pizza
# I18N_Eggplant Parmesan
# I18N_Italian Ice Cream
# I18N_This is some random paragraph without child tags.
# I18N_Delicious homebaked pizza.$8.99 pp
# I18N_Try the authentic Italian flavor of baked aubergine.$6.99 pp
# I18N_Our dessert specialty$3.99 pp
############################################################

###Output with 'joined.replace_with(i18n_string)' ENABLED:#####
# I18N_Pizza
# I18N_Eggplant Parmesan
# I18N_Italian Ice Cream
# Traceback (most recent call last):
  # File "./test.py", line 41, in <module>
    # joined.replace_with(i18n_string)
# AttributeError: 'unicode' object has no attribute 'replace_with'
############################################################

在该线程中，提到了另一种基于isinstance的解决方案，但我无法做到这一点。

如果我理解正确，那么join函数会联接字符串，但返回一个“ unicode”对象，而不是一个字符串对象，这就是为什么“ replace_with”属性不起作用的原因。我该如何解决？非常感谢您的帮助。

Answer 1

replace_with()方法不起作用不是因为joined是unicode对象，而是因为它是bs4对象专用的方法。看到这个：BeautifulSoup-replace_with

通过join()方法返回str的方式，请参见：python3-join

现在为您提供解决方案，我只需在string标记后删除p：

from bs4 import BeautifulSoup

with open("index.html", "r") as f:
 soup = BeautifulSoup(f, "lxml")

f = open("I18N_index.html", "w+")

for h2 in soup.find_all('h2'):
    i18n_string = "I18N_"+h2.string
    h2.string.replace_with(i18n_string)
    print(h2.string)

for p in soup.find_all('p'):
    joined = ''.join(p.strings)
    i18n_string = "I18N_"+joined
    p.replace_with(i18n_string)
    print (i18n_string)


f.write(str(soup))

输出：

I18N_Pizza I18N_Eggplant Parmesan I18N_Italian Ice Cream I18N_This is some random paragraph without child tags. I18N_Delicious homebaked pizza.$8.99 pp I18N_Try the authentic Italian flavor of baked aubergine.$6.99 pp I18N_Our dessert specialty.$3.99 pp

Answer 2

使用简化的代码版本（即仅解决p标签问题），您似乎必须将p.string替换为p.text：

soup = BeautifulSoup（[您的html]，“ lxml”）

 for p in soup.find_all('p'):
   print('before: ',p.text)
   i18n_string = "I18N_"+p.text
   print('after ',i18n_string)

输出：

before:  This is some random paragraph without child tags.
after  I18N_This is some random paragraph without child tags.
before:  Delicious homebaked pizza.$8.99 pp
after  I18N_Delicious homebaked pizza.$8.99 pp
before:  Try the authentic Italian flavor of baked aubergine.$6.99 pp
after  I18N_Try the authentic Italian flavor of baked aubergine.$6.99 pp
before:  Our dessert specialty.$3.99 pp
after  I18N_Our dessert specialty.$3.99 pp

如何使BeautifulSoup的“ replace_with”属性与“ unicode”对象一起使用？

2 个答案: