问题描述
考虑这个简单的代码:
from tkinter import *
from tkinter.ttk import *
root= Tk()
ttk.Label(root, text='Heading Here').grid(row=1, column=1)
ttk.Separator(root,orient=HORIZONTAL).grid(row=2, columnspan=5)
root.mainloop()
当我运行此代码时，它显示错误
when i run this code it's showing error
ttk.Label(root, text='Heading Here').grid(row=1, column=1)
NameError: name 'ttk' is not defined
推荐答案
当您执行 import X 时，您正在导入一个名为 X 的模块.从现在开始，X 将被定义.
When you do import X, you are importing a module named X. From this point on, X will be defined.
当你做from X import *时，你不是导入X，你只是导入里面的东西X 的 .X 本身将是未定义的.
When you do from X import *, you are not importing X, you are only importing the things that are inside of X. X itself will be undefined.
因此，当您执行 from tkinter.ttk import * 时，您不是在导入 ttk，您只是在导入 in ttk.这将导入诸如Label、Button 等内容，但不会ttk 本身.
Thus, when you do from tkinter.ttk import *, you are not importing ttk, you are only importing the things in ttk. This will import things such as Label, Button, etc, but not ttk itself.
在python3中导入ttk的正确方法是使用以下语句:
The proper way to import ttk in python3 is with the following statement:
from tkinter import ttk
有了这个，你可以用ttk.Label引用ttk标签，用ttk.Button等引用ttk按钮
With that, you can reference the ttk label with ttk.Label, the ttk button as ttk.Button, etc.
注意:执行 from tkinter.ttk import * 是危险的.不幸的是，ttk 和 tkinter 都导出同名的类.如果您同时执行 from tkinter import * 和 from tkinter.ttk import *，您将用另一个类覆盖一个类.导入的顺序将改变您的代码的行为方式.
Note: doing from tkinter.ttk import * is dangerous. Unfortunately, ttk and tkinter both export classes with the same name. If you do both from tkinter import * and from tkinter.ttk import *, you will be overriding one class with another. The order of the imports will change how your code behaves.
出于这个原因——特别是在 tkinter 和 ttk 的情况下，每个类都有几个重叠的类——应该避免通配符导入.PEP8，官方 Python 风格指南，正式禁止通配符导入:
For this reason -- particularly in the case of tkinter and ttk which each have several classes that overlap -- wildcard imports should be avoided. PEP8, the official python style guide, officially discourages wildcard imports:
应避免通配符导入( from import * )，因为它们使命名空间中存在哪些名称变得不清楚，使读者和许多自动化工具都感到困惑.
注意:您的问题暗示您使用的是 python 3，但如果您使用的是 python 2，则可以执行 import ttk 而不是 from tkinter import ttk.ttk 在 python 3 中移动.
Note: your question implies you're using python 3, but in case you're using python 2 you can just do import ttk rather than from tkinter import ttk. ttk moved in python 3.
这篇关于为什么 tkinter ttk 显示“名称 ttk 未定义"?在 python 3.5.1 中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！