Question

所以我知道我不应该使用像这样的全局变量，但如果我要将var声明为全局变量，我将如何从另一个函数访问它。这似乎对我没用。请注意，我使用的是python 3.6

from bs4 import BeautifulSoup
import requests
import urllib.request


def f1():                                     
   url = "some url"
   source_code = requests.get(url)
   plain_text = source_code.text
   soup = BeautifulSoup(plain_text, "html.parser")
   for td in soup.find_all('td'):
      global tlist
      tlist = list(td)
      print(tlist)


def cleaned():
   global tlist
   print(global tlist)

Answer 1

print (global tlist)是语法错误;你可以通过单独的global语句使其工作。

>>> def f1():
...     global x
...     x = 1
... 

>>> def f2():
...     print(global x)
  File "<stdin>", line 2
    print(global x)
               ^
SyntaxError: invalid syntax
>>> def f2():
...     global x
...     print(x)
... 
>>> f1()
>>> f2()
1

Answer 2

您可以使用setattr：

x = XClass()
setattr( x, 'my_attr_name', 'value' )
print x.my_attr_name

Answer 3

定义清理方法时出现语法错误。它应该工作，请检查;

from bs4 import BeautifulSoup
import requests
import urllib.request


def f1():                                     
   url = "some url"
   source_code = requests.get(url)
   plain_text = source_code.text
   soup = BeautifulSoup(plain_text, "html.parser")
   for td in soup.find_all('td'):
      global tlist
      tlist = list(td)
      print(tlist)


def cleaned():
   global tlist
   print(tlist)

python中的全局变量不能正常工作？

3 个答案: