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  Decision Trees in C#

Decision trees are simple predictive models which map input attributes to a target value using simple conditional rules. Trees are commonly used in problems whose solutions must be readily understandable or explainable by humans, such as in computer-aided diagnostics and credit analysis. Download source code Download sample applications Download the full Accord.NET Framework Introduction Decision Trees give a direct and intuitive way for obtaining the classification of a new instance f...

   C#,Decision tree     2012-03-23 10:00:56

  Understanding GoLang interface

If goroutine and channel are considered as the foundation for GoLang concurrency, interface would be the key for data types in GoLang. In practical Go programming, almost all data types are built/used around interfaces, interface is the core of GoLang data structures. Go is not a typical OOP language, it has no class and inheritance concept syntactically. But it doesn't mean that there cannot be polymorphism in GoLang. Because of interface, it achieves the same polymorphism effect as in C++, tho...

   INTERFACE,GOLANG     2021-05-15 04:16:42

  Python Performance Tips, Part 1

To read the Zen of Python, type import this in your Python interpreter. A sharp reader new to Python will notice the word “interpreter”, and realize that Python is another scripting language. “It must be slow!” No question about it: Python program does not run as fast or efficiently as compiled languages. Even Python advocates will tell you performance is the area that Python is not good for. However, YouTube has proven Python is capable of serving 40 million videos...

   Python,Performance,Efficiency,Tips     2012-02-14 10:50:22

  Functional Programming For Object Oriented Programmers

After recently remarking about how I finally "got" functional programming I was asked by one of my millions of twitter followers... ¬_¬ to write up an explanation of a small F# program spoken in terms that fellow O-O programmers would understand. Before I become too entrenched into the functional programming way of thinking, that is, and can't explain it anymore. As a former tutor this is one of the major problems with being able to teach something once you understand it. You've ...

   Functional programming,OOP,F#,Pattern     2011-11-25 13:49:16

  Is Java Set ordered or not?

“Is Java Set ordered or not? ” is the most popular question asked when you interview for a Java Developer position. Many fail to answer it, and I have to admit I was one of the many. I have known the answer is “Yes and No” for a long time. No. HashSet is not ordered. Yes.TreeSet is ordered. If the interviewer continues with some follow up questions, I’m not confident that I know the answer then. Why is TreeSet ordered? Are there any other ordered S...

   ORDER,SORTEDSET,HASHSET,JAVA     2021-02-11 06:55:00

  "Programmer" is an Overgeneralization

"Beware of bugs in the above code; I have only proved it correct, not tried it." - Donald Knuth Earlier today, I came across a post during a google-fu session that claimed that no one should use the C++ standard library function make_heap, because almost nobody uses it correctly. I immediately started mentally ranting about how utterly ridiculous this claim is, because anyone whose gone to a basic algorithm class would know how to properly use make_heap. Then I started thinking about all the ...

   Programmer,Overgeneration,Overload     2012-03-13 08:13:16

  Speed Hashing

A given hash uniquely represents a file, or any arbitrary collection of data. At least in theory. This is a 128-bit MD5 hash you're looking at above, so it can represent at most 2128 unique items, or 340 trillion trillion trillion. In reality the usable space is substantially less; you can start seeing significant collisions once you've filled half the space, but half of an impossibly large number is still impossibly large. Back in 2005, I wondered about the difference between a checksum and...

   Speed hashing,Security,MD5     2012-04-07 10:35:15

  The Greatest Developer Fallacy Or The Wisest Words You’ll Ever Hear?

"I will learn it when I need it"! I've heard that phrase a lot over the years; it seems like a highly pragmatic attitude to foster when you're in an industry as fast-paced as software development. On some level it actually IS quite pragmatic, but on another level I am annoyed by the phrase. It has become a mantra for our whole industry which hasn't changed said industry for the better. The problem is this, in the guise of sounding like a wise and practical developer, people use it as an exc...

   Tips, Programming, Expert     2011-04-06 11:07:43

  Text editor vs IDE

A meaningless editor war Many people like to debate which editor is the best. The biggest controversy is between Emacs and vi. vi supporters like to say: "Look it's very fast to type in vi, our fingers no need to leave the keyboard, we even no need to use the up,down,left and right keys" Emacs supporters often downplayed this and said: "What's the use of typing fast if I just need to press one key and it equals to dozens keys you type in vi?"In fact, there is another group of people who like to ...

   Editor,IDE,Structured editor,vi     2013-05-20 12:03:39

  Create cron job on CentOS

These two days, I am building a website and deploying it on a VPS server which uses CentOS 5. I don't have cPanel or Plesk for my account, so I need to install and configure everything myself including Apache, PHP, MySQL and FTP server, also today's topic cron job. Since my website has a ranking algorithm to calculate the rankings of each link and update the ranking on database and I need to calculate the rankings every 5 minutes, so I think to use cron jobs. Here are what I have done which may ...

   cron job,crontab,CentOS,linux,php,example     2012-06-11 09:23:45

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