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   Python – parallelizing CPU-bound tasks with multiprocessing

In a previous post on Python threads, I briefly mentioned that threads are unsuitable for CPU-bound tasks, and multiprocessing should be used instead. Here I want to demonstrate this with benchmark numbers, also showing that creating multiple processes in Python is just as simple as creating multiple threads. First, let’s pick a simple computation to use for the benchmarking. I don’t want it to be completely artificial, so I’ll use a dumbed-down version of factorization...

   Python,Multitasking,Multiprocessing,CPU bound     2012-01-17 11:38:22

  <=> operator in MySQL

Have you ever seen "<=>" in a SQL query while using MySQL? Does it mean less and equals to and greater than? Actually if you consider it as the union of <= and =>, great, you are close to it. This is one form of equal operator in MySQL, it has the similar meaning to the = operator with some subtle difference. According to MySQL documentation, <=> is NULL-safe equal. This operator performs an equality comparison like the = operator, but returns 1 rather than NULL if both operand...

   MySQL,NULL safe,<=>     2014-03-24 06:23:22

  A Perl Regular Expression That Matches Prime Numbers

perl -lne '(1x$_) =~ /^1?$|^(11+?)\1+$/ || print "$_ is prime"' Can you figure out how it works? I give an explanation below, but try to figure it out yourself. Here is what happens when you run it: $ perl -lne '(1x$_) =~ /^1?$|^(11+?)\1+$/ || print "$_ is prime"' 1 2 2 is prime 3 3 is prime 4 5 5 is prime 6 7 7 is prime 8 9 10 11 11 is prime Here is how it works. First, the number is converted in its unary representation by (1x$_). For example, the number 5 gets converted into 1x5, which is ...

   Perl,Regex,Regular expression,Prime number,One line     2011-12-26 08:42:00

  Test-Driven Development? Give me a break...

Update: At the bottom of this post, I've linked to two large and quite different discussions of this post, both of which are worth reading... Update 2: If the contents of this post make you angry, okay. It was written somewhat brashly. But, if the title alone makes you angry, and you decide this is an article about "Why Testing Code Sucks" without having read it, you've missed the point. Or I explained it badly :-)Some things programmers say can be massive red flags. When I h...

   Test driven,Application design,tool     2011-10-17 10:19:16

  Sending message to Slack Incoming Webhook using PHP

Slack is a popular work collaboration tool and it provides many features which help teams collaborate. It has one function which allows sending messages to channels from external source such as your own web service -- Incoming Webhook. This is extremely useful when want to monitor something and get notified when some event occurs and it doesn't require complicated setup. To send messages using Incoming Webhook, a service URL has to be generated on Slack and then the message can be posted to this...

   PHP,CURL,SLACK,INCOMING WEBHOOK     2017-03-11 21:32:28

  Make Magento 2 Faster: Five Quick tips

In this post, you will learn from Magento development company experts about speeding up the Magento 2. We hope these tips will help you in making Magento 2 faster than before. Magento 2 is a powerful platform. Once installed and with no customization it is a fully functional store. They even give you a well-designed, responsive storefront. However as you add products and your own content things will incrementally begin to slow down. To combat that there are some things you can do to increase spe...

   MAGENTO,MAGENTO TUTORIAL,MAGENTO DEVELOPMENT     2016-07-14 00:17:45

  How to Asynchronously Upload Files Using HTML5 and Ajax

In my previous posts, we discovered How to Use HTML5 File Drag & Drop, and Open Files Using HTML5 and JavaScript. Now we have a valid set of files, it possible to upload each one to the server. The process occurs asynchronously in the background so the user can complete other on-page tasks while it occurs.The HTMLLet’s examine our HTML form again:view plainprint?<form id="upload" action="upload.php" method="POST" enctype="multipart/form-data"> ...

   HTML5,File upload,AJAX,Asynchronously,X-FILENAME     2011-10-29 13:45:00

  Programming Language Readability

Lets compare some Python to Haskell for solving the same problem.  The problem we’ll pick is Trie data-structure for auto-completions.  We are interested not so much in the nitty gritty of the algorithm, but in the language style itself.  Auto-complete has been in the programming news a lot recently; both a Python and a Haskell solver have turned up. (I suspect this post got flagged on Hacker News :(  It never got on the front-page despite the rapid upvoting on a n...

   Programming,Readability,Python,Haskell     2012-02-27 04:52:02

  ByteBuffer in Java

ByteBuffer is introduced in java.nio since Java 1.4. It provides a way of representing raw structured data such as from a file or from network. It enables fast access of underlying data compared to traditional ways like byte[] Prior to Java 1.4, if you want to represent a structured raw data, you need to create a byte[] and then having a set of checks to delimit the byte array to get the expected tokens. There are three ways to create a ByteBuffer: Wrapping an exiting array by calling ByteBuffe...

   JAVA,BYTEBUFFER,ALLOCATION     2015-07-08 03:17:44

  Set up Superset on ubuntu 16.04 LTS

Apache Superset (incubating) is a modern, enterprise-ready business intelligence web application. Compared with business-focused BI tool like Tableau, superset is more technology-navy. It supports more types of visualization and able to work in distributed manner to boost the query performance. Most importantly, it is free of charge! An example dashboard: Let’s go and set it up. Create a virtualenv Assume Anaconda is installed for python management. # create a virtualenv with python 3.6 co...

   TUTORIAL,UBUNTU,SUPERSET     2019-10-19 21:34:55

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