Import module
Before using a module, you must import the module in the file where you write the code
Use the keyword import
Example: importing os modules
import os
Import multiple modules
# ① The module name can be followed by import, separated by English commas import random,os,request,math #② Each module is imported separately using the import keyword import random import os import request import math
After importing modules, view the modules imported in the current environment
dir()
import random print(dir())
Output:
['__annotations__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', 'random']
To view all the methods of the imported module, view through dir (module name)
import random print(dir(random))
Output: all classes, methods, and properties of the module
['BPF', 'LOG4', 'NV_MAGICCONST', 'RECIP_BPF', 'Random', 'SG_MAGICCONST', 'SystemRandom', 'TWOPI', '_Sequence', '_Set', '__all__', '__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', '__package__', '__spec__', '_accumulate', '_acos', '_bisect', '_ceil', '_cos', '_e', '_exp', '_inst', '_log', '_os', '_pi', '_random', '_repeat', '_sha512', '_sin', '_sqrt', '_test', '_test_generator', '_urandom', '_warn', 'betavariate', 'choice', 'choices', 'expovariate', 'gammavariate', 'gauss', 'getrandbits', 'getstate', 'lognormvariate', 'normalvariate', 'paretovariate', 'randint', 'random', 'randrange', 'sample', 'seed', 'setstate', 'shuffle', 'triangular', 'uniform', 'vonmisesvariate', 'weibullvariate']
Import package
Package is to place many module files in the same group of folders. This folder is called package or class library. There must be at least one in each package__ init__.py file
Packages can contain sub packages. There should also be in the sub package__ init__.py file
Import entire package
import packageName
Import a module or sub package from a package
imporrt packageName .module
When importing a module or sub package into a package, the import order must follow the path information of the file
Import statement from import...
Import classes, methods, properties, etc. from the module
from followed by module name,
import is followed by the name of the class or method to be imported
Duplicate modules and packages
Rename the imported module and package, and use the keyword as to implement it
The keyword as can only name a package or a module file
import random as rd
Reload modules and packages
Without interrupting the program, when the code of the imported module or package changes, the program will not be updated in real time. Python provides the reload() method of importlib module to reload the module or package
File a.py
def run(): return 10
File b.py
import a
import time
from importlib import reload
if __name__=='__main__':
while 1:
reload(a)
v=a.run()
print("b Modular run()The return value is:",v)
time.sleep(30)
After running the b.py file, modify the return value of a.py to 22;
Output:
b Modular run()The return value is: 10 b Modular run()The return value is: 10 b Modular run()The return value is: 22
Dynamically add modules and packages
Through built-in functions__ import__ () method implementation
Syntax:
__import __(name, globals, locals, fromlist, level)
The required parameter is: name. Character type: string, usually name
import os
import time
from importlib import reload
#Reload function is imported to reload the module
if __name__=='__main__':
this_file=os.path.split(__file__)[-1]#Intercept the file name of the current file path
while 1:
#os.listdir(os.getcwd())
for f in os.listdir(os.getcwd()):#Traverses the list of all files in the current folder
if '.py' in f and f !=this_file:# The filter suffix is py and exclude the current file
file_name = f.split('.')[0]#Intercept the file name of a file without suffix
print("The file to import is",file_name)
new_import = __import__(file_name)#Use__ inmport__ Function dynamic import module
reload(file_name)
v = new_import.run()#How to call the module
print("b Modular run()The return value is:",v)
time.sleep(30)
output
The file to import is a b Modular run()The return value is: 22
__ file__ Property to view the source file path of the module
Run in module file:
print(__fiele__)
Returns the file path of the current module
d:/TestFile/CodePractice/ReptilePractice-12/test1227/b.py
View the source file path of the specified module
Module name. __file__
Package / install custom modules and packages;
When some functions are developed and encapsulated into modules or packages, if you want to share these functions with others, you need to package them.
Others get your packaged module and need to install it before calling it
pack
Built in module package setuptools can package customized modules or packages into whl documents;
Packaging steps:
1. Under the root directory of the project, add setup Py file
Add a mypack folder under the test folder, and then add a setup Py file
2. In setup Py file, specify the name, version, author and other attributes of the package
Use the built-in function setup function of the packaging module setuptools
from setuptools import setup setup( name='mypackage1', #Package name version='1.0', #edition description='This is my practice.',# Function description of packer py_modules=['a','b'], #py module file to package packages=['mypack'], #Packaged module or package path )
- Run the build command in the root directory (see the online tutorial for this step, but it doesn't matter if I don't execute it)
4. Run the package command
On the command line, enter setup Py file, run the following command to view the help information of setuptools
python setup.py --help-commands
function:
python setup.py sdist bdist_wheel
5. View the completed package under the generated dist directory
Packaging command
Package into wheel file
sdist bdist_wheel
Pack into a compressed package
sdist
Install custom packages
Install the package
Enter the directory where the compressed package is located to run
pip install XXXX.tar.gz
Or (install wheel file):
pip install XXx.whl
It can also be installed directly (this should be run in the root directory of the package. I haven't tried yet)
python setup.py install
View all currently installed packages through the pip list command, and you can see the packages I typed myself
Installing third-party modules and packages
pip, a Python package management tool, provides functions such as finding, downloading, installing and uninstalling modules or packages
function
pip help
View help information
Commands: install Install packages. download Download packages. uninstall Uninstall packages. freeze Output installed packages in requirements format. list List installed packages. show Show information about installed packages. check Verify installed packages have compatible dependencies. config Manage local and global configuration. search Search PyPI for packages. cache Inspect and manage pip's wheel cache. wheel Build wheels from your requirements. hash Compute hashes of package archives. completion A helper command used for command completion. debug Show information useful for debugging. help Show help for commands.
Common methods:
Install, install package (parameter - r batch install dependency according to requirements file, - e install editable package; - t install to specified location)
download, download
Uninstall, uninstall
list to view all installed packages and modules
pip install packagesname
freeze instruction
The pip management tool provides the free instruction, which can write the information of the third-party module or package installed in the current environment into requirements txt ； Execute install requirements. In the new environment Txt file, the pip tool will batch install the packages and modules in the file
Enter the file directory to run:
pip freeze > requirements.txt
The current folder automatically generates requirements Txt file;
Copy the file to the new environment and run:
pip install -r requirements.txt
The program automatically performs the installation