Question

导入的模块，connection_status_message.py：

connection_status_message = "Not Connected"

尝试使用Except文件，connect_to_server.py：

from Server.connection_status_message import connection_status_message

def connect_to_server(host,user,password):
    try:
        connect(host,user,password)
    except NoConnection:
        connection_status_message = "Could not reach host..."
        return
...

问题是该变量试图成为本地变量。所以我读了这个问题并看到了如何引用一个全局变量：

def connect_to_server(host,user,password):
    try:
        connect(host,user,password)
    except NoConnection:
        global connection_status_message
        connection_status_message = "Could not reach host..."
        return
...

但现在PyCharm正在声明顶部的import语句已不再使用。

如何使用此Try / Except来使用导入的变量？

Answer 1

我无法复制您的问题，但如果您的import行存储在某个函数下，则该变量为nonlocal instead of global：

def connect_to_server(host,user,password):
    try:
        connect(host,user,password)
    except NoConnection:
        nonlocal connection_status_message
        connection_status_message = "Could not reach host..."

另一种方法是不将变量直接加载到命名空间中，这样就可以参考它来自哪里来避免创建局部变量：

from Server import connection_status_message as csm
csm.connection_status_message

# "No Connection"

def func():    
    csm.connection_status_message = "Could not reach host..."

csm.connection_status_message

# "Could not reach host..."

您也可以考虑创建一个类来处理所有这些作为对象：

class Connection(object):
    def __init__(self):
        self.connection_status_message = "No Connection"
        # TODO: initialize your class

    def connect(self, host, user, password):
        # TODO code connect criteria stuff here

    def connect_to_server(self, host, user, password):
        try:
            self.connect(host,user,password)
        except NoConnection:
            self.connection_status_message = "Could not reach host..."
            # ... return whatever ...#

现在您可以执行from Server import Connection并创建一个本地Connection对象进行操作：

conn = Connection()
conn.connect_to_server(host, user, password)

这可能是显而易见的，但无论如何，该值仅在执行期间存储在内存中。实际的connection_status_message.py永远不会使用此值进行更新。

Python尝试除了不使用导入的变量

1 个答案: