1. Content Review
Object-oriented
Class variable Method : Static method Class method : Binding method : Attribute property
Singleton Module
Singleton module: design mode
Singleton scenarios
_u new_u(self): Instance creation, working before init
logging module
Logged
Logging errors, operation logs
For programmers to see: 1 Statistical use; 2 used for troubleshooting (debug); 3 record errors, complete optimization code.
logging.basicconig:1 Easy to use,2 Implementable,Coding problems;Cannot output to both file and screen.
logging.debug,logging.warning
-
logger object:
Complex: 1. Create a logger object; (2) Create a file operator; (3) Create a screen operator; (4) Create a format; Bind file operators to logger objects Bind screen operators to logger objects Format File Operators Format Screen Operators Use the logger object to operate on. import logging logger=logging.getLogger() fh=logging.FileHandler('log.log') sh=logging.StreamHandler() logger.addHandler(fh) logger.addHandler(sh) formatter=logging.Formatter('%(asctime)s-%(name)s-%(levelname)s-%(message)s') sh.setFormatter(formatter) fh.setFormatter(formatter) logger.warning('message')
collections module
from collections import OrderedDict
odic=OrderedDict([('a',1),('b',2),('c',3)])
print(odic)
# # odic['k']='k1'
# # odic['k1']='k2'
for k,v in odic.items():
print(k,v)#Module namedtuple
#There is no way to create a class where the values of all properties cannot be modified
from collections import namedtuple
Course=namedtuple('course',['name','price','teacher'])
python=Course('python',1980,'lexm')
print(python)
print(python.name)
=======================
course(name='python', price=1980, teacher='lexm')
python
====
//Read-only property: t property cannot be modified
import time
t=time.localtime()
print(t)Project Development Specification
supplement
- Stack, FIFO, lifo
- Queue, fifo is queue, fifo
reflex
hasattr
setattr
getattr
class A:
@staticmethod
def func():
print('12345')
getattr(A,)
delattrGet instance variables, binding methods from objects
Get class variables, class methods, static methods from classes
Get any variable in the module (common variable, function, class) by the module name
Get any variables in this file from a text file.
getttr(sys.modules[__name__],'Variable Name')
Abstract Class/Interface Class
Is to give a specification to a subclass so that it must implement the method in accordance with the specification of an abstract class.
class Foo:
def func(self):
raise NotImplementedError
class Son(Foo):
pass
s=Son()
s.func()Modules and packages
Module: The py file is written and provides some functionality directly to the programmer.
import,from import
What is a package:
Folder, a folder that stores multiple py files.
If a package is imported, the modules in this package will not be available by default.
The contents of the u init_u.py file need to be completed.
Importing a package is equivalent to executing the contents of an init.py file.
Project Specification
bin start #import os，sys #base_path=os.path.dirname(os.path.dirname(__file__))#Current File #sys.path.append(base_path) #from src import core conf setting src Business logic student.py from src import core core.py from conf import settings db data file lib enlarge file log log file
Module Summary
os: operating system(Job: Calculate folder size, considering absolute path)
os.path.getsize('d:\code\s21')
#file
#file
#Route
#listdir,walk
sys
#The sys.path module searches for paths, and whether a module can be imported depends on whether there is a path for the module in sys.path.
#sys.argv, get command line parameters, python c://aaa.py remove file path
#sys.module, which stores all modules used in the current program and reflects the contents of the file.
json，Supports all languages
#Serialization, converting other types to str/bytes
#json format:
#1 All strings are double quotes
#2 The outermost layer can only be a list or a dictionary
#3 supports int float str list dict bool only
#4 A key with a dictionary can only be str
#5 cannot load multiple times in a row
pickle，Only supported py
#1 All data types can be written to a file
#2 Support continuous load multiple times
random(Operations, red bags, no one gets the same probability of amount, a total of 200 yuan, decimal inaccuracy ( print(random.uniform(1,5)))
import random
random.choice([1,2,3,4])#Randomly pick one
random.sample([1,2,3,4,5],3)#Extract Multiple
#randint
#choice
#sample
#Shuffle, shuffle, algorithm
time
#Timestamp
#sleep() causes the program to pause ns
hashlib(Jobs, check file consistency, files, videos, pictures)
#md5
#sha
#import hashlib
#hashlib.md5('xxl'.encode()) -- Change MD5 to sha here if the sha algorithm is used
#md5.update('str'.encode())
#print(md5.hexdigest())
datetime
from datetime import datetime
dt=datetime.now()
print(datetime.timestamp(dt))
#now()
#utc()
#strftime('%Y-%m-%d') gets a datetime object
#timedelta(days=140), the addition of time
#Fromtimestamp timestamp to datetime
#timestamp(datetime object), datetime to timestamp
pickle
shutil
#import
shutil.make_archive()Compressed file, shutil.unpack_archive()Unzip the file, shutil.retree()Delete directory, shutil.move(),move file
#importlib
#import importlib
#importlib.import_module('module name')
#print(os.path.isdir('xxx')) to determine if it is a directory, isfile, or file
copy
getpass，Show in command line ciphertext
copy
logging
#Two configurations: basicconfig,logger
collections
#OderdDict,namedtuple,deque,defaultDict
functools
#reduce(add,iterable)
Object-oriented
Three main features: encapsulation, inheritance, polymorphism #Encapsulation: (1) Generalized encapsulation: members of a class (2) Narrow encapsulation: private members, u names, are only used inside a class and cannot be called outside. #Inheritance, all lookup names (invocation methods and properties) are first to find themselves, not their own parent #If you and your parent have both, you want both to be called, and super() specifies the class name to be called directly 1. Parent, Base, Superclass (2) Derived classes, subclasses (3) Multiple inheritance, search order, depth first, breadth first (4) Single inheritance, subclasses can use the method of the parent class #Polymorphism -Multiple states represented by one class and similar states represented by multiple classes -user class, user class -vip_user -svip_user 1 Duck type #vip_user,svip_user #list,tuple Basic concepts: #What is a class: A class of things with the same methods and attributes #What is an object, an instance: a specific individual with specific attribute values and actions #Instantiation: The process of getting a specific object from a class #Instance #Instantiation Combination: #Objects of one class as instance variables of objects of another class Class members: class variables, binding methods, Special member: class method classmethod Static method:staticmethod property: Special Members Double Bottom Method, Magic Method, Built-in Method #__str__ _u new_u, construction method _u init_u, Initialization Method __dict__ _u call_u, object can be used with parentheses _u enter_u, u exit_u, with context management __getitem__ __setitem__ __delitem__ _u add_u, two objects added __iter__ __dict__ Related built-in functions: isinstance, object and class issubclass, class, and class Type, type, class=type (object) super follows mro order to find the previous class's New and Classic Classes: py2 inherits object s as new-style classes #Classic class by default py3 are all new-style classes, inheriting object s by default New Class: #Inherit object Supports super Multiple Inheritance, Width First mro method Classic Classes: #py2 does not inherit object s #No super syntax #Multiple Inheritance Depth First No mro method