Programmer Think

matplotlib Drawing function plot plot: draw a two-dimensional graph to connect the points of the plane import numpy as np import matplotlib.pyplot as plt x = np.linspace(-np.pi, np.pi, 256,endpoint=True) plt.plot(x,np.cos(x)) # x-axis y-axis plt.show() # Finally, enter this # If the x-axis is not specified, it will be 0,1,2 n-1 scatter ...

definition: Real life is mostly subject to Poisson distribution Suppose you work in a call center, how many calls will you receive in a day? It can be any number. Now, the total number of calls in a call center in a day can be modeled by Poisson distribution. Here are some examples: The number of emergency calls recorded by the hospital i ...

it happened like this The little brother of python development who is preparing to leave work Got a call from my girlfriend that she's going to work overtime tonight And send him a self photo with a blurred background As follows ↓↓ The sensitive little brother is suspicious. Will there be a cap of forgiveness Then python ro ...

Basic principle: logical XOR operation Python is a programming language without much introduction; OpenCV is a cross platform computer vision and machine learning (partially open source) software library based on BSD license. At present, it has supported many languages, such as C, C + +, python, Java and MATLAB. Here, choose one of the langua ...

Example 1: 77 combination 77. Portfolio This question is mainly to understand the basic use of backtracking algorithm. Take the given n=4,k=2 as an example (source: Code Capriccio) As can be seen from the above figure, the logic of the code is to insert for loop traversal in recursion. The exit condition of a recursive loop is when the path ...

Basic operation of SparkStreaming in PySpark preface Stream data has the following characteristics: • data arrives quickly and continuously, and the potential size may be endless • numerous data sources and complex formats • large amount of data, but do not pay much attention to storage. Once processed, it will either be discar ...

What I wrote earlier: recording the content of video coding course is for learning and consolidation. I hope you can correct what's wrong. Thank you very much. There are few introductions, mainly to facilitate their own review. I don't want to listen and study in class, so I read the paper with my roommate. I think back to the video coding cont ...

(first of all, when creating this project, Baidu's robots agreement only banned taobao, so my crawler is legal. But now Baidu's robots have been changed, so this article does not attach the complete code) [project preview] [creative background] After learning about crawlers, I first created a program to climb today's headlines. Then my hus ...

The title comes up casually. It deceives you to click in to learn reptiles. Should it be no problem? This article belongs to the simulated Login series. In fact, the one sent a few days ago is also: In order to help you better roll in the winter vacation, I wrote an open class downloader of Chinese University MOOC~ The goal of this article is ...

XML (eXtensible Markup Language) refers to eXtensible Markup Language, which is designed to transmit and store data. It has increasingly become the core of many new technologies and has different applications in different fields. It is the inevitable product of the development of web to a certain stage. It not only has the core characteristics ...