SEARCH KEYWORD -- string format


  How does Base64 work

Base64 is a data encoding scheme used in safe data transfer such as HTTP and its extensions. Base64 encoding can conver arbitrary group of bytes into a sequence of readable ASCII characters. These converted characters can safely put in a HTTP header without causing any problem while the peers process the HTTP header. Base64 encoding was invented as part of the MIME content transfer encoding. It is similar to other encoding schemes such as Uuencode and BinHex but with higher efficiency....

   ALGORITHM,BASE64     2016-03-09 23:47:40

  Python basics summary

Python is recommended by many people as the first language to be learned now. Even in some universities, it is the primary language to be taught to CS/CE students. To master this languages, we should understand some basics of it. Here we summarize some basics about this language. These basics include : string replacement with regular expression, traverse a directory, sort a list, remove duplication, dictionary ordering, dictionary, list, string conversion, date object manipulation, command line ...

   Python,Summary     2013-09-23 10:04:42

  Memory related exception analysis in Java

Java Virtual Machine Specification divides the memory of JVM into several areas : Heap, Stack, The Program Counter register and Method area etc. In HotSpot JVM, heap is composed of Young, Tenured and Perm. There are different OutOfMemory error can happen in different memory area. Next is an overview of some of these OOM errors. StackOverflowError The JVM will allow only a specified number of stacks created nested. An JVM option -Xss can be set to determine the maximum stack size. If the num...

   Java, Memory model, Memory exception, OOM     2015-01-19 06:54:27

  Use cases of Java enumeration

JDK 1.5 introduces a new type -- enumeration. In Java, it's just a small feature, but it can bring us much convenience.Here we summarize some use cases of Java enumeration. 1. Constant Prior to JDK 1.5, we can define constant as public static final..., now we can use enumeration to group all constants in one enum variable and it also provides some useful functions. public enum Color {     RED, GREEN, BLANK, YELLOW   }  2.In Swit...

   Java, Enum,enumeration     2013-01-05 09:15:30

  JSP connect MySQL

To connect MySQL with Java Server Page(JSP). Some steps should be followed:Step 1: Download MySQL JDBC connector driver from the Internet. URL:  http://dev.mysql.com/downloads/connector/j/Step 2: Put the jar file downloaded in Step 1 in the Tomcat common lib folder and add this jar file to the CLASSPATH so that the JSP page can find the specified class.Step 3: Create the JSP page with MySQL connection : Example is shown below:        <% String driver="com.mysql.j...

   MySQL,JSP,Connection,Driver,Download     2011-05-11 10:04:57

  Start to work with rollup.js to pack JS files

rollup.js is a module bundler for JavaScript. It compiles small piece of JavaScript modules spreading in different files into a single larger standardized ES code file. This post will show some entry level usage for this library. Introduction Normally a bundler tool would compile a few small JavaScript files into a single JavaScript so that web browser can read, parse and render it properly. A bundler tool may be needed because of a few reasons: Some early stage browsers don't understand module...

   ROLLUP.JS,COMMONJS,ES MODULE,BUNDLE,WEBPACK     2022-06-12 00:00:14

  jQuery to check whether checkbox is checked

In Vanilla JavaScript, the correct way of checking whether a checkbox is checked is to get the property checked of the checkbox. Assuming there is an checkbox with id "checkbox1", below line will return true if the checkbox is checked while it will return false if the checkbox is unchecked: document.getElementById("checkbox1").checked In jQuery, there are a few ways to check this. The first one is to using the corresponding counterpart of the Vanilla JavaScript, it is to check the checked proper...

   jQuery,checked,checkbox,attr,prop     2015-07-25 08:49:54

  Save QWidget as image

Qt library is an excellent GUI library for C++ programmers developed by Nokia and now is an open source project. Often, we may use QPainter to draw strings, lines or images on a QWidget. We can override the QWidget's paintEvent() method when we want to use QPianter object to draw something on a QWidget. If we want to save the items drawn on QWidget as image for later reference, what can we do? We can save a QWidget as an image. Here is the code for achieving this: QPixmap pixmap(this->size())...

   Qt,C++,QWidget,Image     2012-08-19 12:01:18

  Cleansing data with Pig and storing JSON format to HBase with Pig UDF

Introduction This post will explain you the way to clean data and store JSON format to HBase. Hadoop architect experts also explain Apache Pig and its advantages in Hadoop in this post. Read more and find out how they do it. This post contains steps to do some basic clean the duplication data and convert the data to JSON format to store to HBase. Actually, we have some built-in lib to parse JSON in Pig but it is important to manipulate the JSON data in Java code before store to HBase. Apache Pig...

   JSON,HADOOP ARCHITECT,APACHE HBASE,PIG UDF     2016-06-10 01:13:41

  PHP to output string to client terminal

It is a common task to echo messages to the user using PHP. There are lots of ways where the message can be echoed to the client terminal(browser or console window) through PHP. These includes some well know debug methods like var_dump() and var_export() etc. In this post, we will show you some other methods shared by Laruence, one of the core members of PHP development team. 1. echo First comes with the most common one : echo. $str = "Hello PHP\n"; echo $str; 2. print Then comes another c...

   TRICKS,DEBUG,OUTPUT,PHP     2015-10-01 03:16:56

RECENT