table of Contents
Module basis -> how import module
python modules commonly used: numpy / pandas / matplotlib (data analysis must be proficient <Data analysis was performed using the python>)
29 pm -> module, regardless of atm
Module
python as your phone -> pip as steward Applications -> module is the application software
Module Category:
Module system comes -> no need to install
You need to download the module
Custom modules
Built-in module: python interpreter built-in module to start, time / random / os / sys ...
Installation module pip: pip install jieba / pycharm installation
Custom Module -> custom code
Package (block)
What is a module?
Module -> code implements a specific function -> easier
import time 和 from ......import.py
import time
The program runs to import time this line, it will automatically perform the following three steps:
1, opening up memory space, memory space named time:
2, all the code is read into time.py namespace, and then run
3, by the time. The method of use of the name of the time module
time.sleep(1)
from module import name method name
from time import sleep
The program runs to import time this line, it will automatically perform the following three steps:
1, opening up memory space, memory space named time:
2, all the code is read into time.py namespace, and then run
3, the sleep () reads the import and form ... import.py, a method name can be used directly
sleep(0.01)
If you want to use multiple methods, proceed as follows:
from time import sleep, time, # write the name of the method you want to use in the import behind, separated by commas
If you want to import all methods
from time import * # import all the features
The advantages and disadvantages of both
import
Advantages: Never conflict
Cons: multiple input several characters when you call inconvenient
from ...... import......
Advantages: less input characters when calling
Disadvantages: prone to conflict
Custom Modules
Their own definition of a module to prepare for call
Use of custom modules: sub-file storing code, a function to separate the functions, diamagnetic more clearly, specific module is responsible for specific functions
Circulation import
When the cycle import method with the basic method, will complain (not into the loop, because once open only to the module memory space)
There are two solutions:
First, before importing define objects to be imported
Second, the definition of the object to be introduced in the function because the function detects only the syntax, the code is not performed
The module search path
Mainly refers to the module search path:
1, memory
2, built-in
3, custom
Memory -> Built -> Customize
Two uses python file
First, as an executable file: The current file is run the executable file
Second, as the module file: it is introduced into other executable file
__name__ is unique to each file.
When the file is run as an execution file, __ name __ equal to '__ main __';
When the document file is imported as a module, __ name __ equal to the file name