pyspark basics

Java basics-annotations and java Basics Annotation is a form of metadata that provides non-program data and has no direct impact on the annotated code. This article mainly summarizes the usage of comments. java platform (SE) pre-defined comments. Type comments are used with the pluggable type system for stronger type checks, and how to implement repeated comments. Annotations have many functions, including:

Java basics-generic 1 and java Basics The use of generics can make the type name as a parameter in the class or interface definition, just like a common parameter, so that the defined type is more universal. Advantages of generics: Strict type check for compilation The java compiler is more rigorous in checking the type of generic code and can detect some runtime errors in common code. Eliminate type

Java basics-network programming, java basics Network Programming I. IP and InetAddress Java supports the development of network communication programs. It mainly provides two communication protocols: TCP and UDP. Reliable connection and transmission, and third-party handshake Unreliable connection transmission, which is not necessarily acceptable to the receiver during transmission All network program d

() sets the Date object's month field and day number fields (World time) Date.setutcseconds () to set the Date object The seconds field and the Millisecond field (at the time of the World) Date.setyear () sets the Date object's Year field date.todatestring () to return dates as a string date.togmtstring () to convert date to world time words Character string date.tolocaledatestring () returns the date part of a Date object as a locally formatted string date.tolocalestring () Converts a da

Iterators are divided into two types: one is iterator and the other is const_iterator.Both can access the elements in the container, and the difference is:(1) The Const_iterator type can only be used to read elements within a container, cannot change its value, and iterator may change its value.(2) When a const_iterator type is dereferenced, the return value is a const value and does not allow the assignment of its dereference.Also do not confuse the Const_iterator object with the Const iterator

ListBoxAlert (oListBox.option.length)//Get the number of options in the listboxB. Get or set the selected itemalert (Olistbox.selectedindex); Gets or sets the index of the selected itemAlert (olistbox.options[olistbox.selectedindex].text)//Gets the text of the selected itemOlistbox.selectedindex =-1; setting is not selected5. Delete Options Remove an option function Dal (index) //Index of the item to delete { var olistbox = document.getElementById ("Selage");

Thinkphp BASICS (1) and thinkphp Basics The ThinkPHP directory is as follows. Application is the meaning of the Application (our code is put here), and Public is the meaning of Public files (mainly for front-end resource files such as js css ), the ThinkPHP file is the core package of the Framework (we generally do not operate on it ). This means that the background staff should write code in the Applica

#include #includestring>#includeusing namespacestd; //declaring a string copy functionChar* MYSTRCPY (Char* STR1,Const Char*str2);classcperson{Char*M_pname; Public: CPerson (Char*pName) {cout"Common Constructors"Endl; M_pname=New Char[Strlen (PName) +1]; if(m_pname) {mystrcpy (m_pname, pName); } }//copy constructor, make only bit-mode copy, i.e. shallow copy//CPerson (CPerson p)// {//m_pname = p.m_pname; // } //Deep Copy ConstructorsCPerson (CPerson p) {cout"Deep Copy Constructors"En

Php basics (2): php Basics Embed PHP code on the Web page Default syntax Short tag Script ASP Style Embed multiple code blocks Add comments to code Single Row C ++ syntax Shell syntax Multi-line C syntax Output data to the browser Print () Statement Echo () Statement Printf () Statement Sprintf () Statement Data Types supported by PHP Scalar Data Type Co

Pig C ++ note BASICS (5) expressions and statements, pig BasicsPig C ++ note BASICS (Part 5) Keywords: expressions, statements The content in this chapter is relatively simple, and there is basically no difficulty in understanding it. It is a matter of knowledge. I was not prepared to write it first, but now I have to take notes and write it. After all, there are some gains. So, I just put forward some poin

Development and defense of mobile games-II. BASICS (Continuous updates) and basics of mobile game development Sorry, this article is not available until now because of the recent expansion of company members, technical training, and project issues. Okay, let's not talk about anything else. This article is suitable for people who have some knowledge about the basic components of Unity and want to know how t

Shell BASICS (9) functions, shell Basics Functions allow us to divide a complex function into several modules, so that the program structure is clearer and the code reuse rate is higher. Like other programming languages, Shell also supports functions. Shell functions must be defined before use1. The Definition Format of Shell functions is as follows: [function] fun_name () {command1[retrun n]} The return V

Css BASICS (1): css Basics Css Reference Manual: css.doyoe.com In css3, different browsers may require different prefixes, indicating that the css attribute or rule has not yet become part of W3C standards and is a private attribute of the browser, although the latest versions of browsers do not require prefixes, it is necessary to better forward compatible prefixes. -Webkit indicates chrome and safari pri

Html BASICS (1): html Basics Html5 Document declaration: You can insert script, Style File css, and various meta information into the head element. The tag elements that can be added to the header area include Define the title in the browser toolbar Provide the title when the page is added to favorites Page title displayed in search engine results Defines page encoding, UTF-8 multi-language encoding, a

Javascript basics, basics of photography for beginners Javascript Introduction Javascript has three important components: ECMAScript, DOM, and BOM. ECMAScript is the core language defined by ECMA specifications. In fact, this language does not contain input and output definitions. The ECMA Specification defines only the basis of this language, on which a more complete scripting language can be built. Our

Java BASICS (19) IO streams (2), java basics io streams Here are some of the knowledge points and code I summarized in my previous class. Most of the notes I think are very good and classic, sincerely hope that these will help those who want to learn! It is inconvenient to upload code by module. There are also many things, and they are also clear! If you need it, you can leave your email in the comments. I

Java BASICS (12) Summary of common classes (2) and java Basics Here are some of the knowledge points and code I summarized in my previous class. Most of the notes I think are very good and classic, sincerely hope that these will help those who want to learn! It is inconvenient to upload code by module. There are also many things, and they are also clear! If you need it, you can leave your email in the comme

Java BASICS (5): java Basics Here are some of the knowledge points and code I summarized in my previous class. Most of the notes I think are very good and classic, sincerely hope that these will help those who want to learn! It is inconvenient to upload code by module. There are also many things, and they are also clear! If you need it, you can leave your email in the comments. I will certainly send it to y

Java BASICS (6) Object-oriented (1) and java basics object-oriented Here are some of the knowledge points and code I summarized in my previous class. Most of the notes I think are very good and classic, sincerely hope that these will help those who want to learn! It is inconvenient to upload code by module. There are also many things, and they are also clear! If you need it, you can leave your email in the

Java BASICS (7) Object-oriented (2), java basics object-oriented Here are some of the knowledge points and code I summarized in my previous class. Most of the notes I think are very good and classic, sincerely hope that these will help those who want to learn! It is inconvenient to upload code by module. There are also many things, and they are also clear! If you need it, you can leave your email in the com