Question

我该怎么办？我想要一个条目，但是这个错误是什么?????

def gt():
    global e
    string = e.get() 
    print(string)  
def p():
    b.destroy()
    c.destroy()
    w = Label(top, text="here are what you can use:")
    w1 = Label(top, text="qwertyuiop[]asdfghjkl;zxcvbnm,./QWERTYUIOPASDFGHJKLZXCVBNM123456789")
    w.pack()
    w1.pack()
    L1 = Label(top, text="give me the password")
    L1.pack( side = LEFT)
    e=Entry(top)
    e.pack()
    r = Button(top,text='okay',command=gt)
    r.pack(side='bottom')
    top.mainloop()

错误：

Traceback (most recent call last):
  File "C:\Python33\lib\idlelib\run.py", line 121, in main
    seq, request = rpc.request_queue.get(block=True, timeout=0.05)
  File "C:\Python33\lib\queue.py", line 175, in get
    raise Empty
queue.Empty

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Python33\lib\tkinter\__init__.py", line 1475, in __call__
    return self.func(*args)
  File "C:\Users\Hadi\Desktop\t.py", line 51, in gt
    string = e.get()
NameError: global name 'e' is not defined

我该如何修复此代码？ e已定义，但它表示它不是!!!!？

Answer 1

函数内部使用

global来通知函数使用外部/全局变量而不是本地变量。它不会创建全局变量。

要创建全局变量，您必须使用外部函数，即

e = None    # or any other value

然后你必须在global e中使用p()来告知函数你要将Entry()分配给外部/全局变量，而函数不必创建局部变量{{ 1}}

顺便说一句：您甚至可以跳过# create global variable - you have to assign any value - ie. `None` e = None def gt(): # global e # you don't need "global" because you doesn't assign new value using `=` print(e.get()) def p(): # inform function to use external/global variable instead of local one global e # you need it because you use `=` to assign new value e = Entry(top) e.pack()，因为e = None加global e会创建全局变量（e = Entry() with global e不会创建全局变量）。

有时候更好地使用e = ...，因为它可以为读取您的代码的人提供有用的信息。

tkinter中的条目错误

1 个答案: