对openpyxl、python3的疑惑

Question

He guys, I am just a beginner in Python3. I have a question:

import openpyxl
from openpyxl.style import * 

As you can see that I am importing the openpyxl module, but why I need to import the second one in order to style fonts and cells an on.

Answer 1

openpyxl is a package. It contains modules, such as style . You should import the package anyway (all package or individual items). You can either:

import openpyxl
from openpyxl.style import *

then use style items like item1 , item2 or

from openpyxl import style

then use style items like style.item1 , style.item2

Answer 2

You don't have to - you can just as easily do:

import openpyxl
openpyxl.styles.fonts()

Or:

from openpyxl import style
style.fonts()

It comes down to personal preference. Using * imports is generally frowned upon because there's a risk of polluting the namespace, but if you know this isn't going to happen, and you want to keep your lines of code shorter, it's acceptable.

Answer 3

You are importing openpyxl, which includes everything in openpyxl including openpyxl.style and everything inside that. But say you would like to use X function of openpyxl.style, then you would have to write:

openpyxl.style.X() 

If you write the second line you can simpy write:

X()

Basically the second line imports all the contents of the namespace openpyxl.style into your current namespace, removing the hassle of having to write openpyxl.style. everytime. Although it is generally a good practice to not merge namespaces like this, and not use

from _________ import *

Rather you can write

import openpyxl.style as op

and then use the X function as:

op.X()

You can also omit the line

import openpyxl 

if you are not using anything else from openpyxl other than that included in openpyxl.style