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Pdf (Portable Document Format), Chinese name "Portable Document Format", is a file format we often come into contact with. Documents, documents Many are in PDF format. With the advantage of stable format, it enables us to optimally maintain the original color and format in the process of printing, sharing and transmission.   PDF ...

Official website: https://pandas.pydata.org/docs/reference/api/pandas.DataFrame.aggregate.html objective The main line of this article is to explore the basic usage of agg and the corresponding applicable scenarios, and finally make a simple exploration of the source code layer. 1. This paper introduces the parameters of agg and its demo 2. ...

**Freight service network design: reading notes of classic literature (2) **It was mentioned that the model used in cranic T g (1984) should be reproduced, but the general framework given in the article is still too general. After trying, it was decided to use Netplan (1989) for LCL freight proposed by Jacques Roy & Louis Delorme on the bas ...

data structure Introduction A brief history of the future: Dataism Problem solving: What Why How a feasible method based on the finite point of view Turing machine calculation model Algorithm and computational complexity Computable problem: the difficulty of the algorithm Non computable problem: boundary or limit Breaking th ...

preface In April, he joined a data-oriented artificial intelligence enterprise in Nanjing as a python crawler intern. In addition to writing scripts for Python crawlers, this position also has a job of text markup. Text marking can be regarded as a process of sorting and cleaning data manually. Although it is boring, it is also an essential li ...

Branch and loop Process control - controls the sequence of code execution Sequential structure: the code is executed from top to bottom, and each statement is executed only once. (default) Branch structure: select whether to execute or not to execute part of the code according to the conditions. (use if) age = int (input("Please enter your ...

Stacking integration algorithm can be understood as a two-layer integration. The first layer contains multiple basic classifiers to provide the prediction results (meta features) to the second layer, while the classifier of the second layer is usually logistic regression. He takes the results of the first layer classifier as features to fit ...

Here I recommend my official account number: programmer sailing. Windows development history Microsoft Windows At first, it was developed by Microsoft in 1985 and gradually became the most popular version of Microsoft's operating system. MS-Dos Version numberRelease timeWindows1.01985.11Windows2.01987.12Windows2.11988Windows3.01990.5Windo ...

1, Vectorization and broadcasting The concepts of vectorization and broadcasting are the basis of numpy's internal implementation. With vectorization, you don't need to use explicit loops when writing code. These loops can not be omitted, but are implemented internally and replaced by other structures in the code. The application of vectorizat ...

selenium driver has its own delay function, which is divided into explicit waiting and implicit waiting. To sum up briefly: Explicit wait: it is mainly for an element to be visible, clickable, etc. within the specified time. If it exceeds the time, an exception will be thrown. Implicit waiting: it is mainly facing the whole page. The next ste ...