Tutorial by Examples: l

Single characters can be extracted using array (square brace) syntax as well as curly brace syntax. These two syntaxes will only return a single character from the string. If more than one character is needed, a function will be required, i.e.- substr Strings, like everything in PHP, are 0-indexed....

TestNG requires JDK 7 or higher to use. According to http://testng.org/doc/download.html in order to install testng you need to add testng dependency to your maven pom.xml or gradle build.gradle file Maven: <repositories> <repository> <id>jcenter</id> <name...

Creating a list of KeyValuePair: Dictionary<int, int> dictionary = new Dictionary<int, int>(); List<KeyValuePair<int, int>> list = new List<KeyValuePair<int, int>>(); list.AddRange(dictionary); Creating a list of keys: Dictionary<int, int> dictionary ...

To delete a file (if you have required permissions) is as simple as: File.Delete(path); However many things may go wrong: You do not have required permissions (UnauthorizedAccessException is thrown). File may be in use by someone else (IOException is thrown). File cannot be deleted because ...

To change a text file is not easy because its content must be moved around. For small files easiest method is to read its content in memory and then write back modified text. In this example we read all lines from a file and drop all blank lines then we write back to original path: File.WriteAllLi...

Text is saved encoded (see also Strings topic) then sometimes you may need to change its encoding, this example assumes (for simplicity) that file is not too big and it can be entirely read in memory: public static void ConvertEncoding(string path, Encoding from, Encoding to) { File.WriteAllT...

This example updates last write time of a huge number of files (using System.IO.Directory.EnumerateFiles instead of System.IO.Directory.GetFiles()). Optionally you can specify a search pattern (default is "*.*" and eventually search through a directory tree (not only the specified director...

This snippet is an helper function to enumerate all files older than a specified age, it's useful - for example - when you have to delete old log files or old cached data. static IEnumerable<string> EnumerateAllFilesOlderThan( TimeSpan maximumAge, ...

Having example type like this: public TestClass { public static string StaticPublicField = "StaticPublicFieldValue"; } We can retrieve value of StaticPublicField: var fieldExpr = Expression.Field(null, typeof(TestClass), "StaticPublicField"); var labmda = Expression....

echo off cls sqlcmd.exe -S "your server name" -U "sql user name" -P "sql password" -d "name of databse" -Q "here you may write your query/stored procedure" Batch files like these can be used to automate tasks, for example to make backups of ...

Basic Error Handling By default, Express will look for an 'error' view in the /views directory to render. Simply create the 'error' view and place it in the views directory to handle errors. Errors are written with the error message, status and stack trace, for example: views/error.pug html bo...

It is obvious to assume that the percentage value of margin to margin-left and margin-right would be relative to its parent element. .parent { width : 500px; height: 300px; } .child { width : 100px; height: 100px; margin-left: 10%; /* (parentWidth * 10/100) => 50px ...

Detailed instructions on getting aspectj set up or installed.

To use opacity in all versions of IE, the order is: .transparent-element { /* for IE 8 & 9 */ -ms-filter:"progid:DXImageTransform.Microsoft.Alpha(Opacity=60)"; // IE8 /* works in IE 8 & 9 too, but also 5, 6, 7 */ filter: alpha(opacity=60); // IE 5-7 /* Modern Browse...

This command has several related yet distinct forms. del v If v is a variable, the command del v removes the variable from its scope. For example: x = 5 print(x) # out: 5 del x print(x) # NameError: name 'f' is not defined Note that del is a binding occurence, which means that unless expl...

If you want to log exceptions you can and should make use of the logging.exception(msg) method: >>> import logging >>> logging.basicConfig() >>> try: ... raise Exception('foo') ... except: ... logging.exception('bar') ... ERROR:root:bar Traceback (most rec...

The flip flop operator .. is used between two conditions in a conditional statement: (1..5).select do |e| e if (e == 2) .. (e == 4) end # => [2, 3, 4] The condition evaluates to false until the first part becomes true. Then it evaluates to true until the second part becomes true. After t...

This simple example shows how to start multiple threads in Java. Note that the threads are not guaranteed to execute in order, and the execution ordering may vary for each run. public class HelloMultithreading { public static void main(String[] args) { for (int i = 0; i < 10; i...

Prerequisites JDK 7 or Higher (Recommended: JDK 8+) Adding Bukkit as a Dependency The simplest method to add the Bukkit API to your project is to download the Bukkit.jar directly from the Spigot Repository and add it to your project's classpath. Legacy versions of Bukkit can be found at the...

We can create a better mapper classes with extension methods, Suppose if i have some DTO classes like public class UserDTO { public AddressDTO Address { get; set; } } public class AddressDTO { public string Name { get; set; } } and i need to map to corresponding v...