Python

A magic method is a method that is wrapped up in __ __, and can be called to the corresponding magic method without invoking the method directly or invoking other functions. This spelling means that the name has a special meaning, and do not use it

A lot of people sometimes just need to get a fixed line in the article, so I know this line, how do I need to get it?Someone might say read this line, if this line is already what the beginning of the reading out,In fact, there is another way, is

Turn from: Pseudo-computer scientist | Real Yard FarmFirst introduce a simple and very practical tool, that is multiprocessing. Pool. If your task can be solved with YS = map (f, XS), as you probably know, this form is inherently the easiest to

if __name__ " __main__ " : main ()　　The purpose of this if statement is to allow the programmer to run the module as a standalone program, or to import it in another module;ExplainEach Python module has a set of built-in module variables that are

Pythonnet Network 4Select supports horizontal triggeringPoll support level triggeringEpollEpoll is also an IO multiplexing approach, with a higher efficiency than select and poll.Epoll not only supports horizontal triggering, but also supports edge

What is a threadIn traditional operating systems, each process has an address space, and there is a control thread by defaultThread as the name implies, is a pipeline work process (pipeline work needs power, power is equivalent to the CPU), and a

listing: [] list:The list is not only a different data type, but also a large amount of data, compared to strings. Lists are ordered, (in order of preservation), indexes can be sliced1. Indexes and slices:LST = ["Twist Vine", "Wang Jianlin", "Ma Yun"

Python 3.6.5attributes and definitions of tuplesAnd the list type is just [] changed to ()Characteristics:1. Immutable (the tuple itself is immutable, but can be stored as an element of a mutable type) {Guess because the address of the variable

Control flow StatementsThere are three control flow statements in Python-- if , for and while .ifStatementifStatement to check the condition: If the condition is true (true), we will run a block of statements (called If-block or if blocks),

Queue description　　Processes are isolated from each other, and to implement interprocess communication (IPC), the Multiprocessing module supports two forms: queues and pipelines, both of which use message passingCreate a queue class (the underlying

Review:strings, like tuples, can only be read and cannot be written. Lists and dictionaries can nest anything, lists can be nestedL = List ("Hello") # L = [' h ', ' e ', ' l ', ' l ', ' O ']3. Collection OperationsA set is a combination of unordered

# Coding=utf-8From selenium import WebdriverImport timeBrowser=webdriver. Firefox ()#browser. Maximize_window () # window maximizationBrowser.get (' https://www.baidu.com ') # accessing Baidu in the current browserPrint ("title:" +browser.title,end=

Dictionary (DIC)1. Definition and formatEnclosed in {} braces, the dictionary (DIC) is the key:value to hold the data.Eg:dic = {"Timely Rain": "Song Jiang", "Jade Kylin": "Lu Junyi", "mastermind": "WU"}This is a dictionary.Format is Key:vlaueThe key

First, the crawler principle:Automatically get the data you need from the Web by simulating browser behaviorSecond, the crawler's process1. Send request to a URL:2, get the returned response parse to get the data needed to do the various processing

IO in the computer middle finger input/output by the CPU this ultra-fast compute core to execute, involves the data exchange place, usually is the disk, the network and so on, needs the IO interface.In IO programming, stream (stream) is a very

1 input () function to implement user input, the program will stop waiting for input, get the user's input and continuemessage = input ("tellme something,and I-'ll repreat itback-to-you:") print (message)2 using int to get numeric inputAge = input

Requirements: Remove the contents of the basket box and write to the CSV file. Each row is taken out as an element in a new array with two for loops.1 #Coding=utf-82 fromSeleniumImportWebdriver3 fromTimeImportSleep4 Importkeyword5

In Python, we sometimes need to consider the complexity of the algorithm we design, first in Python provides a built-in module that can be used to test the complexity of our algorithm, and then see the use of this module Timeit, first we import the

Main Learning Contents: dictionary operationAn increase in the search and deletion1. dict[does not exist key] = value, SetDefault () Dict.setdefault ("A", "B") A is to find the key, if there is a then return value, if none, increase B2. Pop (key).

Pillow IntroductionThe properties of the image class: 1, Format 2, Mode 3, Size 4, Palette 5, InfoFunctions of Class II: 1, New 2, Open 3, Blend 4, Composite 5, Eval 6, Frombuffer 7, fromstring 8, MergeThird, the image class method: 1, Convert 2,