Programmer Think

catalogue 1, Traverse the entire list (for loop) 1. Simply understand the for loop2. Do more in the for loop3. Perform some operations after the for loop 2, Avoid indenting errors 3, Create a list of values 1. Use the function range()2. Create a list of numbers using range()3. Perform simple statistical calculations on the list of numbers4. ...

1. Write in front In the code examples that will appear in later articles, the code with a prompt (> > >) runs in IDLE, and the code with a prompt (> > >) acts as an input line, otherwise it is an output line.python comments start with a # sign and end at the end of the line. Comments are used to clarify the code and will not ...

Lists and tuple s are two common data structures in Python. Lists and tuples are an ordered collection that can place any data type. In most programming languages, the data types of collections must be consistent. In python, elements in the same list or tuple can be of different types. list=[3,7,'Mar','Feb','Jan'] # The list contains both in ...

Diagram This figure is inaccurate for the underlying implementation method of some implementation classes, which has changed in the new version of JVM, such as HashMap, but the inheritance and implementation relationship has not changed. Solid white arrows are inheritance and blue dashed arrows are implementation. Map HashMap Before ja ...

environment windows 10 64 bitanaconda with python 3.7pdf2docx 0.5.2 preface Converting PDF files into word files is a very common operation. I believe that most people's free solution is to use some online conversion services, but there will be a problem of data leakage. This article introduces an open source free local conversion tool, pdf2d ...

I Why do I need a garbage collection mechanism When a Python program is running, it needs to open up a space in memory to store the temporary variables generated during running; After the calculation is completed, the result is output to the permanent memory. If the amount of data is too large and the memory space is mismanaged, it is easy to ...

Spider What is it? Spider Is a basic class provided by scripy, and other basic classes contained in scripy (such as CrawlSpider )And custom spider s must inherit this class. Spider Is a class that defines how to crawl a website, including how to crawl and how to extract structured data from its web pages. The source code is as follows: The ...

As mentioned earlier, the biggest hidden danger of lazy list is logical deletion, but there is no physical deletion problem. Therefore, EBR first solve d this problem to him. I EBR modification int parse_delete(intset_l_t *set, val_t val) { node_l_t *pred, *curr; int result, validated, isVal; while(1) { //Init pred ...

https://www.oschina.net/question/1449495_149180 java serialization: Java provides a mechanism for object serialization. In this mechanism, an object can be represented as a byte sequence, which includes the data of the object, information about the type of the object and the type of data stored in the object. After a serialized object is wr ...

1, Foreword  details of Java performance optimization affecting performance - continued. I intend to write the whole series of articles with this title slowly. This is the first article entrance . This time, the content mainly comes from the book "actual combat of Java program performance optimization". It is a reading note. Int ...