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  Python internals: adding a new statement to Python

This article is an attempt to better understand how the front-end of Python works. Just reading documentation and source code may be a bit boring, so I’m taking a hands-on approach here: I’m going to add an until statement to Python. All the coding for this article was done against the cutting-edge Py3k branch in the Python Mercurial repository mirror. The until statement Some languages, like Ruby, have an until statement, which is the complement to while (until num == 0 is equi...

   Python,New statement,Research,Addition     2012-03-12 07:32:24

  Python internals: how callables work

[The Python version described in this article is 3.x, more specifically - the 3.3 alpha release of CPython.] The concept of a callable is fundamental in Python. When thinking about what can be "called", the immediately obvious answer is functions. Whether it’s user defined functions (written by you), or builtin functions (most probably implemented in C inside the CPython interpreter), functions were meant to be called, right? Well, there are also methods, but they’re not very ...

   Python,Callable work,Rationale     2012-03-24 05:20:27

  Google search engine algorithm change history

Recently, Google had a major adjustment on its search algorithm: Users can directly see answers to the searched question on the top of the page.There are billion of search requests each day on Google. There is no doubt that the algorithm will become the subject of discussion. Last year, Google did an adjustment to its search algorithm every 17.5 hours in average. We all experience the change of the algorithm. Following information chart summarizes the major changes of Google search algorit...

   Google,Search engine,History,Google+     2012-04-07 12:41:10

  Performance is a Feature

We've always put a heavy emphasis on performance at Stack Overflow and Stack Exchange. Not just because we're performance wonks (guilty!), but because we think speed is a competitive advantage. There's plenty of experimental data proving that the slower your website loads and displays, the less people will use it. [Google found that] the page with 10 results took 0.4 seconds to generate. The page with 30 results took 0.9 seconds. Half a second delay caused a 20% drop in traffic. Half a seco...

   Website,Perfomance,Optimization     2011-07-02 01:52:12

  C Preprocessor Hell

Lisp programmers should stop reading right now because they'll likely suffer severe injury of the jaw muscles as they laugh themselves silly at how hard it is to do some things in C. The C language has a pre-processor (typically called cpp) that is both infuriating and powerful. How powerful is usually best described as 'just too little' and it has happened more than once that I found myself almost - but not quite - able to do what I wanted to do. The frustration can run very deep at ti...

   C,Preprocessor,Lisp,Hell     2012-01-19 10:22:31

  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

  Application vs Database Programming

A few years ago, I had a problem.  A database routine for processing bulk payments for LedgerSMB that was humming along in my test cases was failing when tested under load with real data prior to implementation.  Some testing showed that while it ran fine with small numbers of inputs, it eventually slowed way down as the number of inputs rose.  Andrew Sullivan, who was also on the project through a different company, suggested it was something called a "cache miss" because I...

   Application Programming,Database programming,Comparison,Difference     2012-03-04 12:08:35

  How to increase the productivity of your IT team

  As a manager, when your team isn’t completing as much work as they should be and you’re feeling the pressure from those higher up, it can be difficult to know what to do. The whole team is stressed and productivity is taking a huge drop. When this happens it’s time to take a step back and assess where the issue lies. Here’s how to increase the productivity of your IT team.   Have clear goals and roles At the start of every project have a meeting with everyone...

   PRODUCTIVITY,IT TEAM, BUSISNESS     2018-04-17 06:19:26

  Useful Bash Scripts

Many people hack together shell scripts quickly to do simple tasks, but these soon take on a life of their own. Unfortunately shell scripts are full of subtle effects which result in scripts failing in unusual ways. It's possible to write scripts which minimise these problems. In this article, I explain several techniques for writing robust bash scripts. Use set -u ...

   Linux,Shell,Bash,Command,Robust     2012-01-15 10:28:00

  Writing robust shellling scripts

Many people hack together shell scripts quickly to do simple tasks, but these soon take on a life of their own. Unfortunately shell scripts are full of subtle effects which result in scripts failing in unusual ways. It's possible to write scripts which minimise these problems. In this article, I explain several techniques for writing robust bash scripts. Use set -u ...

   Robust,Shell script,Set,Commands     2012-03-19 13:25:26

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