Empty slice vs nil slice in GoLang

In Go, there is a type called slice which is built on top of array. It's a very convenient type when we want to handle a group of data. This post will explain a subtle but tricky difference between empty slice and nil slice. A nil slice is a slice has a length and capacity of zero and has no underlying array. The zero value of slice is nil. If a slice is declared like below, it is a nil slice. package main import "fmt" func main() { var a []string fmt.Println(a == nil) } The output will be t...

   GOLANG,JSON,EMPTY SLICE,NIL SLICE     2018-10-18 09:25:21

  How DNS lookup works

When accessing a website, a domain name would be needed normally. To get to the actual web server, the domain name must be mapped to an actual IP address and the IP address will be used to reach the web server. The process of finding the IP address from a domain name is called DNS lookup.  How does DNS lookup work? There are tons of domain name and IP address around the world, there must be some well-designed architecture to support fast lookup. This post will explain how this works. DNS Se...

   DNS,DNS LOOKUP     2022-09-09 23:11:03

  Understanding PGO in GoLang 1.20

Background The Go 1.20 version was officially released in February 2023, it introduced the PGO(Profile Guided Optimization) mechanism. The basic principle of PGO can be divided into the following two steps: First, profiling is performed on the program to collect data about the program's runtime and generate a profiling file. When compiling the program, enable the PGO option, and the compiler will optimize the program's performance based on the content in the .pgo file. When compiling a program...

   GO 1.20,PGO,GOLANG     2023-02-28 04:27:46

  Understanding How is Data Stored in RDBMS

We all know that DBMS (database management system) is used to store (a massive amount of) data. However, have you ever wondered how is data stored in DBMS? In this post, we will focus on data storage in RDBMS, the most traditional relational database systems. Physical Storage Data can be stored in many different kinds of medium or devices, from the fastest but costy registers to the slow but cheap hard drives, or even magnetic tapes. Nowadays, IaaS providers such as AWS...

   RDBMS,DATABASE     2019-02-04 09:25:36

  static nested and non-static nested class in Java

Nested classes are divided into two categories: static and non-static(inner). Nested classes that are declared static are simply called static nested classes. Non-static nested classes are called inner classes. Static class can be defined as : class OuterClass{ static class StaticNestedClass{ //OTHER STUFF } } Static nested classes are accessed using the enclosing class name: OuterClass.StaticNestedClass For example, to create an object for the static nested class, use this synta...

   Java,static nested class,inner class     2014-04-23 07:11:44

  Best Rich Text Editors ready to use in web projects

This post illustrates five interesting rich text editors ready to use in your web projects. I also provided some guidelines regarding how to implement them on your pages using a few lines of HTML code. Try them!1. Yahoo! UI Library: Rich Text EditorThe Yahoo! Rich Text Editor is a UI control that replaces a standard HTML textarea and is based on Yahoo! UI Library; it allows for the rich formatting of text content, including common structural treatments like lists, formatting treatments like...

   RTE,Example,Project,Open Source,Best,Sim     2011-07-27 10:57:33

  Is programmer really profession for youth only?

- dedicated to the new programmers just into the workplace.

One young Chinese friend asked me: is programmer meant only for less experienced youth? Should I consider transition once if I work on it until 30 years old?

   Programmer,Youth,Product,Project,Career,Analysis     2012-03-18 07:06:44

  Don't write on the whiteboard

I recently interviewed at a major technology company. I won't mention the name because, honestly, I can't remember whether I signed an NDA, much less how strong it was.I did well. Mostly because of luck. I normally step over myself when I interview. I guess I've improved over the years. Here are a few tips to ace your own interview.1. Don't write on the whiteboardWhen I interviewed at Palantir around 5 years ago, I had a lot of trouble with this. Yes, I knew next to nothing about compu...

   Interview,Preparation,Whiteboard,Note,Python     2012-01-11 11:31:32

  How the Go language improves expressiveness without sacrificing runtime performance

This week there was a discussion on the golang-nuts mailing list about an idiomatic way to update a slice of structs. For example, consider this struct representing a set of counters. type E struct { A, B, C, D int } var e = make([]E, 1000) Updating these counters may take the form for i := range e { e[i].A += 1 e[i].B += 2 e[i].C += 3 e[i].D += 4 } Which is good idiomatic Go code. It's pretty fast too BenchmarkManual 500000 ...

   Go,Expressiveness,Performace,Sacrifice     2012-02-12 04:53:55

  Mozilla releases a web identity system : Persona

Now almost every website requires the user to register, there are many benefits of registration for a website, such as retaining users, accommodating discussions, providing customized content and so on.But there is too much trouble if each site requires registration, right?Of course, users can also have their own way, for those less important sites, for example, using a unified user name, password and email so that you only need to remember one account. Then, we also see some advanced methods em...

   Mozilla,Persona,Security,ID     2012-09-28 12:02:25