为什么 tkinter ttk 在 python 3.5.1 中显示“名称 ttk 未定义”

Question

Consider this simple code:

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()

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

Answer 1

When you do import X , you are importing a module named X . From this point on, X will be defined.

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.

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.

The proper way to import ttk in python3 is with the following statement:

from tkinter import ttk  

With that, you can reference the ttk label with ttk.Label , the ttk button as ttk.Button , etc.

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.

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:

Wildcard imports ( from import * ) should be avoided, as they make it unclear which names are present in the namespace, confusing both readers and many automated tools.

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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.

Answer 2

To import ttk , replace the following line:

from tkinter.ttk import *

with:

from tkinter import ttk

Otherwise, attributes of tkinter.ttk module will be loaded into the current module namespace instead of ttk itself.

Answer 3

When you are importing the ttk module, you can do it in 2 ways -

1. from tkinter import ttk When you do this, ttk is imported almost like a variable, so you can use that ttk.Label

2. from tkinter import * This is called wildcard import. You can't use ttk.Label you have to directly write Label(options)

Answer 4

ttk.Label(root, text='HeadingHere').grid(row=1, column=1) 
NameError: name 'ttk' is not defined
In this remove ttk as follows.    
Label(root, text='HeadingHere').grid(row=1, column=1

Now it works fine