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  Case sensitivity in PHP

Case sensitivity in PHP is a bit messy. We recommend that you stick to the case sensitive rule in any language. Here we share some case sensitivity cases in PHP.1. Case sensitive1.1 Variable name is case sensitiveAll variables names are case sensitive, these include normal variables and superglobals such as $_GET,$_POST,$_REQUEST,$_COOKIE,$_SESSION,$_GLOBALS etc.<?php$abc = 'abcd';echo $abc; //Output 'abcd'echo $aBc; //No outputecho $ABC; //No output1.2 Constant name by default is case sensit...

   PHP,Case sensitivity,Summary     2012-06-25 05:48:17

  Do you still remember things you saw around you as a kid

I believe we all have unforgettable childhood, we might see many weird stuff around us and had deep impression about some cool stuff. Some of the old stuff may extinct now but every time when we saw an item rare to be seen, the old memories may flush into our brain immediately and we would be excited about it. Can you still remember things around you as a kid? Here are some of them, if you were born at 80's or 90's, you may be familiar with these. 1. Windows 95 and Windows 98 We could see these ...

   Childhood,Internet     2013-11-25 08:58:58

  How to forcibly eject a CD/DVD from a MacBook Air USB SuperDrive

So you've got a DVD stuck in the external USB SuperDrive that connects to the MacBook Air? And you've tried hitting the magic Eject button on the keyboard to no avail?And you've tried drutil tray eject at the command-line? And you've tried booting with Option held down and clicking eject? And you've tried plugging the drive into other machines (Macs, Windows PCs, Linux machines) to no avail?What do you do?Clearly you hit the physical eject button, right? Every DVD drive has one of those. On the ...

   Apple,Macbook,USB Drive,Ejection     2011-11-17 08:39:56

  The Go Pointer Magic

Go is a language with the pointer type, by which we can Pass pointer into a function and update value in-place. Add methods to a struct as (* T) A, which is different from (T) A(). However, the pointer is type-safe in Go, meaning that there are such restrictions of the pointer. Different types of pointers are unconvertible. Pointer type cannot be used for calculation. Pointer types cannot be compared, either == nor !=. No mutual assignment between different pointer-...

   GOLANG,POINTER,UNSAFE     2021-10-03 02:18:57

  Why 0.1+0.2 != 0.3

In programming languages such as JavaScript, c/c++, Java and Matlab, you will find that you will get unexpected result when doing float point calculation. For example, when calculating 0.1 + 0.1, you will not get 0.3: > 0.1 + 0.2 == 0.3 false > 0.1 + 0.2 0.30000000000000004 Don't be surprised of this result, this is the end result of IEEE 754 standard, float point number cannot be accurately represented according to IEEE 754 because: No enough memory is allocated for representing the num...

   float point,comparison,JavaScript     2014-11-19 05:32:46

  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

  Do you have this kind of comments in your source code?

Writing runnable code is the essential skill of a programmer, writing understandable comment is also a skill a programmer should acquire. There is some famous saying that bad comment is worth than no comment. Usually your code will be maintained by other people, if you provide them some difficult to understand or misguided comments, this will be nightmare to them. While at some other time, programmers may put some funny comments in their codes which may make others laugh. Today we...

   COMMENT,HUMOR     2016-08-01 10:25:14

  5 Reasons Your Javascript Stinks

Javascript gets a bad rap on the Internet, but there are few languages that are so dynamic, so widespread, and so deeply rooted in our lives as Javascript is. The low barrier of entry leads some people to call it a script kiddie language, others scoff at the concept of a dynamic language while riding their statically typed high horse. You and Javascript just got off on the wrong foot, and now you've made it angry. Here's five reasons why your Javascript code sucks.1. You're not using a namespace...

   JavaScript,Good,Habit,Prototype,OOP     2011-04-13 12:25:37

  Magic CSS shape

There is a question on StackOverflow which states that someone finds a CSS sample on http://css-tricks.com/examples/ShapesOfCSS/  , the sample shows a triangle created with pure CSS. The source code is :#triangle-up {width: 0;height: 0;border-left: 50px solid transparent;border-right: 50px solid transparent;border-bottom: 100px solid red;}The question is how these few lines can create a triangle? Next we give the answer and the detail illustration to this question We need to consider the B...

   CSS,Triangle,Box model,Border     2012-04-20 12:56:22

  How Speeding The "Most Important Algorithm Of Our Lifetime" Could Change This Modern World

Math breakthroughs don't often capture the headlines--but MIT researchers have just made one that could lead to all sorts of amazing technological breakthroughs that in just a few years will touch every hour of your life. Last week at the Association for Computing Machinery's Symposium on Discrete Algorithms (SODA) a new way of calculating Fast Fourier Transforms was presented by a group of MIT researchers. It's possible that under cert...

   FFT,Speed-up,Fast fourier transform     2012-03-20 07:47:04

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