module import call

txt interpretation module

When creating a new package, there will be an init new file 
pip installs the library file When the import import is invalid, 
there are three types of modules: 
standard library, third-party, custom module How to call 
import: 1 Execute the corresponding file 2 Import the variable name 
import cal 
from cal import cal 
from day import cal# don't know cal but know day, the best way 
print(cal.add(3,5))

Function function module cal.py

#This module only puts functions as function modules

def add(x,y):
    return x+y
def sub(x,y):
    return x-y

Execute function module bin.py

# import cal will execute all functions once, 
# # print(cal.add(3,5)) calls the function in the cal module by clicking 
# print(cal.sub(3,5)) 
# #You can run to get the result , but there are red 
# import cal, time can import multiple commas 
# from cal import add 
# from cal import sub 
# from cal import *# This writing is not recommended 
# print(add(3,5)) 
# print(sub (3,5)) 
# import sys 
# print(sys.path) 
# from day import cal# I don't know cal but know day, successful 
# print(cal.add(3,5)) 
# print(cal.sub( 3,5)) 
from day import main
main.run()

main module main.py

#Main file 
from day import main #To execute main, you must first import 
from day import cal
 def run():
     print (cal.add(3,7 ))
     print (cal.sub(3,7))