UnboundLocalError：局部变量

Question

我的代码如下：

search_request = urllib2.Request(url,data=tmp_file_name,headers={'X-Requested-With':'WoMenShi888XMLHttpRequestWin'}) 
#print search_request.get_method() 
try: 
    search_response = urllib2.urlopen(search_request) 
except urllib2.HTTPError: 
    pass 
html_data = search_response.read() 
print html_data 

但是当我运行它，我得到这个：

Traceback (most recent call last): 
    File "G:\MyProjects\python\lfi_tmp.py", line 78, in <module> 
    print hello_lfi() 
    File "G:\MyProjects\python\lfi_tmp.py", line 70, in hello_lfi 
    html_data = search_response.read() 
UnboundLocalError: local variable 'search_response' referenced before assignment 

我尝试添加

global search_response 

，并再次运行，我得到这样的例外

Traceback (most recent call last): 
    File "G:\MyProjects\python\lfi_tmp.py", line 78, in <modul 
    print hello_lfi() 
    File "G:\MyProjects\python\lfi_tmp.py", line 70, in hello_ 
    html_data = search_response.read() 
NameError: global name 'search_response' is not defined 

Answer 1

如果你正在得到HTTPError你没有search_response变量。所以这条线：

html_data = search_response.read() 

提高你的错误，因为你正试图向未声明的访问search_response。我认为你应该更换html_data = search_response.read()线像这样的例子：

search_request = urllib2.Request(url,data=tmp_file_name,headers={'X-Requested-With':'WoMenShi888XMLHttpRequestWin'}) 
    #print search_request.get_method() 
try: 
    search_response = urllib2.urlopen(search_request) 
    html_data = search_response.read() #New here 
except urllib2.HTTPError: 
    html_data = "error" #And here 

print html_data 

Answer 2

的代码下面的代码，其中search_response变量没有设置要去exception。

try: 
    search_response = urllib2.urlopen(search_request) 
except urllib2.HTTPError: 
    pass 
html_data = search_response.read() 
print html_data 

代替使用pass，提高错误或search_response变量设置为None。

也许是这样的：！

try: 
    search_response = urllib2.urlopen(search_request) 
except urllib2.HTTPError: 
    raise SomeError 
html_data = search_response.read() 
print html_data 

或

try: 
    search_response = urllib2.urlopen(search_request) 
except urllib2.HTTPError: 
    search_response = None 
if html_data: 
    html_data = search_response.read() 
    print html_data 
else: 
    # Do something else