Programmer Think

1, Change the shape of the array functioneffectnp.reshape(a, newshape)a is an array and newshape is an integer tuple; Returns an array of newshape shapesnp.ravel(a)Flatten into a one-dimensional array; Equivalent to NP reshape(a, -1)np.flatten(a)The effect is the same as that of t ravel, but flatten is more recommended 1.1 np.reshape() A ...

catalogue 1, Static class 2, Dynamic class Classes are divided into static classes and dynamic classes. Static classes can be understood as a collection of functions with the same characteristics into one class. Dynamic classes are simply understood as instantiated classes. The key difference is that static classes do not have self keyword ...

Installing selenium Open the command control character input: pip install -U selenium Firefox browser installation firebug: www.firebug.com COM, debug all website languages and debug functions Selenium IDE is a plug-in embedded in Firefox browser to realize the recording and playback function of simple browser operation. The script recorded ...

Python project alien invasion (II): Aliens In this chapter, we mainly complete the following functions. First, add an alien at the edge of the screen, and then try to generate a group of aliens. We make these aliens move like two hundred years and below, and delete the aliens hit by the bullet. Finally, we show the number of ships the play ...

1, Basic image processing -- operation All the following functions are omitted cv2. 1.1.1 addition operation As has been said before, for a computer, an image is just a matrix. The addition of images is the addition of matrices. We use the add(a, b) function to realize the image addition operation. Note: when a + B < = 255, a+b = a+b; ...

Depth first search pruning We have learned that the search process will eventually generate a search tree. Pruning, as the name suggests, is to cut down unnecessary subtrees on the search tree through some judgment. Sometimes, we will find that the state of the subtree corresponding to a node is not the result we want, so we don't need to ...

preface We are students of domestic colleges and universities and beginners of quantitative investment. Our school is not reopened in northern Qing Dynasty, nor does it have a financial engineering laboratory. At the same time, it is located in a third tier town. Therefore, it is difficult for us to obtain quantitative internship opportunities ...

1, Understanding PyPI It can be understood that it is a package management platform. All packages we commonly use will be hosted on this platform. Through pip install xx, we will find this package in PyPI and download it to our computer. 2, Process analysis For module developers, there are essentially three things to do: Open the refrig ...

Reading guide Set type is a set of string type, which is characterized by disordered and non repetitive set elements. Each set can store 232 - 1 elements (more than 4 billion) at most. Set type mainly has the following application scenarios. 1. Collection of friends / followers / fans / interested people The unique feature of set typ ...

🌟 Last time we talked about the decision tree algorithm, which is based on sklearn. This time, we want to learn about naive Bayes, what is "naive". The meaning of simplicity is that the features are independent of each other and have no correlation. Small partners interested in previous content can refer to the following content 👇: ...