SEARCH KEYWORD -- RANDOM NUMBER

  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

  The biggest iOS 5 bug you've never heard of

There is a huge bug when Group Messaging is disabled in iOS 5. I'm shocked Apple hasn't fixed this yet. Today a friend sent out a text message blast, announcing they got a new phone number. Shortly after, I got text messages from three random people I don't know. I was confused how these people got my number, but then I realized they were replies intended for my friend who sent out the text blast. If you've ever used the Group Messaging feature,...

   iOS5,Bug,Group Messaging     2011-12-10 06:04:39

  Crazy: 90 Percent of People Don't Know How to Use CTRL+F

This week, I talked with Dan Russell, a search anthropologist at Google, about the time he spends with random people studying how they search for stuff. One statistic blew my mind. 90 percent of people in their studies don't know how to use CTRL/Command + F to find a word in a document or web page! I probably use that trick 20 times per day and yet the vast majority of people don't use it at all."90 percent of the US Internet population does not know that. This is on a sample size of thousa...

   Ctrl-F,Shortcut,Common knowledge,Confusi     2011-09-02 11:16:48

  What are some lesser known but useful Unix commands?

A few that come to mind, some less known, some more: xargs or parallel: run things in parallel, with lots of options sed and awk: more well-known but still super useful for processing text files, and faster than Python or Ruby m4: simple macro processor screen: powerful terminal multiplexing and session persistence yes: print a string a lot cal: nice calendar env: run a command (useful in scripts) look: find English words (or lines in a file) beginning with a string cut and paste and join: data...

   Linux,Unix,Command,Less used     2011-12-27 09:27:49

  How Kafka achieves high throughput low latency

Kafka is a message streaming system with high throughput and low latency. It is widely adopted in lots of big companies. A well configured Kafka cluster can achieve super high throughput with millions of concurrent writes. How Kafka can achieve this? This post will try to explain some technologies used by Kafka. Page cache + Disk sequential write Every time when Kafka receives a record, it will write it to disk file eventually. But if it writes to disk every time it receives a record, it would ...

   BIG DATA,KAFKA     2019-03-08 09:42:57

  "Simplicity" is not a simple concept

I've come to avoid using the word "Simplicity" or its variants ("Simple," &c.) It means too many different things to different people.For example, my original land-line phone was simple:It's simple by eliminating extraneous use cases. It only handles one user scenario, the one that was the most common when it was invented. If we think of the number of affordances and the number of uses, this kind of simplicity lowers the number of affordances by lowering the number of uses. I call this kind ...

   Simplicity,Software,Usability,iPhone,Phone     2011-11-24 09:21:09

  Some frequently used ES6 code snippets

Below are a list of ES6 code snippets which are used frequently. Hope that it will be helpful. 1. Shuffle array elements let arr = [67, true, false, '55'] arr = arr.sort(() => 0.5 - Math.random()) console.log(arr) // [ '55', 67, false, true ] 2. Remove characters which are not numbers const str = 'xieyezi 23213 is 95994 so hansome 223333' const numbers = str.replace(/\D/g, '') console.log(numbers) // 2321395994223333 3. Reverse sequence or words const sentence = 'xieyezi js so handsome, lol.'...

   JAVASCRIPT,ES6,CODE SNIPPET,TIPS     2022-04-10 07:56:07

  People, processes and tools

Some years ago, one of my managers used to repeat this "Accenture truism" (or so he designated it): to fix or improve something, first you need the right people, then you need the right processes to help those people work together, then finally you need the right tools to support those processes. People, processes, and tools - in that order.This is even more true for tech startups than for corporations. As geeks, whenever we face a problem, we often start by looking for a tool to fix it. "Our te...

   Work,People,Process,Tool,Importance,Priority     2011-10-24 11:36:14

  Python: calculate lighter/darker RGB colors

Many times color palettes have lighter and darker variations of the same color. This may be used to convey relative importance, or for something as simple as a gradient. Usually the designer will specify both colors. However, if you have a site that needs to allow user configurable styling, you may not want to ask the user for two variations of the same color. Here is some Python code to take a single color in RGB, and output an artitrarily lighter or darker variation of the same color...

   Python,RGC color,Calucaltion lighter/darker     2012-02-13 05:29:22

  How to Create Dynamic PDF with Image and Content in Asp.Net Development?

Aegissofttech .net developers are specialized in developing real time web applications. While working on one of such real time web app development projects, our asp.net development team discovered an easy way to create PDF template from user inputs. The developers used Java Script and web service to accomplish PDF template development. To learn how to develop these dynamic PDF with content and graphics, you can follow the below tutorial. In real time web applications, we often require to generat...

   asp.net development,     2015-04-27 01:11:40

RECENT