Tutorial by Examples: d

To keep a container running in the background, supply the -d command line option during container startup: docker run -d busybox top The option -d runs the container in detached mode. It is also equivalent to -d=true. A container in detached mode cannot be removed automatically when it stops, t...

Auto-implemented properties were introduced in C# 3. An auto-implemented property is declared with an empty getter and setter (accessors): public bool IsValid { get; set; } When an auto-implemented property is written in your code, the compiler creates a private anonymous field that can only be...

Lets assume we have some Film model: public class Film { public string Title { get; set; } public string Category { get; set; } public int Year { get; set; } } Group by Category property: foreach (var grp in films.GroupBy(f => f.Category)) { var groupCategory = grp.Key; ...

Overview In order to debug Java classes that are called during MATLAB execution, it is necessary to perform two steps: Run MATLAB in JVM debugging mode. Attach a Java debugger to the MATLAB process. When MATLAB is started in JVM debugging mode, the following message appears in the command wi...

Constants are declared like variables, but using the const keyword: const Greeting string = "Hello World" const Years int = 10 const Truth bool = true Like for variables, names starting with an upper case letter are exported (public), names starting with lower case are not. // not e...

Change Index Initialize or update a particular element in the array array[10]="elevenths element" # because it's starting with 0 3.1 Append Modify array, adding elements to the end if no subscript is specified. array+=('fourth element' 'fifth element') Replace the entire ar...

C++17 C++17 introduces structured bindings, which makes it even easier to deal with multiple return types, as you do not need to rely upon std::tie() or do any manual tuple unpacking: std::map<std::string, int> m; // insert an element into the map and check if insertion succeeded auto [i...

To get a verbose list of all devices connected to adb, write the following command in your terminal: adb devices -l Example Output List of devices attached ZX1G425DC6 device usb:336592896X product:shamu model:Nexus_6 device:shamu 013e4e127e59a868 device usb:337641472X produc...

Write the following command in your terminal: adb shell getprop This will print all available information in the form of key/value pairs. You can just read specific information by appending the name of a specific key to the command. For example: adb shell getprop ro.product.model Here are a...

While composer provides a system to manage dependencies for PHP projects (e.g. from Packagist), it can also notably serve as an autoloader, specifying where to look for specific namespaces or include generic function files. It starts with the composer.json file: { // ... "autoload&q...

After creating a new model or modifying existing models, you will need to generate migrations for your changes and then apply the migrations to the specified database. This can be done by using the Django's built-in migrations system. Using the manage.py utility when in the project root directory: ...

You can use traits to modify methods of a class, using traits in stackable fashion. The following example shows how traits can be stacked. The ordering of the traits are important. Using different order of traits, different behavior is achieved. class Ball { def roll(ball : String) = println(&q...

We can name our loops and break the specific one when necessary. outerloop: for (var i = 0;i<3;i++){ innerloup: for (var j = 0;j <3; j++){ console.log(i); console.log(j); if (j == 1){ break outerloop; } } } Output: 0 0...

While many people think that ^ means the start of a string, it actually means start of a line. For an actual start of string anchor use, \A. The string hello\nworld (or more clearly) hello world Would be matched by the regular expressions ^h, ^w and \Ah but not by \Aw

With IronPython you can access any .net assembly which is compiled using the same or a lower version than the IronPython core. Example: Importing a a .net assembly and class from System import Math Example: Using an imported class: from System import Math print Math.Abs(-123) You can also lo...

Method GetCustomAttributes returns an array of custom attributes applied to the member. After retrieving this array you can search for one or more specific attributes. var attribute = typeof(MyClass).GetCustomAttributes().OfType<MyCustomAttribute>().Single(); Or iterate through them forea...

To find out the IP address of your container, use: docker inspect <container id> | grep IPAddress or use docker inspect docker inspect --format '{{ .NetworkSettings.IPAddress }}' ${CID}

Payments Table CustomerPayment_typeAmountPeterCredit100PeterCredit300JohnCredit1000JohnDebit500 select customer, sum(case when payment_type = 'credit' then amount else 0 end) as credit, sum(case when payment_type = 'debit' then amount else 0 end) as debit from payments group by ...

Classes have 3 types of methods: instance, singleton and class methods. Instance Methods These are methods that can be called from an instance of the class. class Thing def somemethod puts "something" end end foo = Thing.new # create an instance of the class foo.somemeth...

Hash has a default value for keys that are requested but don't exist (nil): a = {} p a[ :b ] # => nil When creating a new Hash, one can specify the default: b = Hash.new 'puppy' p b[ :b ] # => 'puppy' Hash.new also takes a block, which allows you to automatically create n...