Tutorial by Examples: ble

It is possible to query an object about its instance variables using instance_variables, instance_variable_defined?, and instance_variable_get, and modify them using instance_variable_set and remove_instance_variable: class Foo attr_reader :bar def initialize @bar = 42 end end f = F...

The Kernel exposes methods for getting the list of global_variables and local_variables: cats = 42 $demo = "in progress" p global_variables.sort #=> [:$!, :$", :$$, :$&, :$', :$*, :$+, :$,, :$-0, :$-F, :$-I, :$-K, :$-W, :$-a, #=> :$-d, :$-i, :$-l, :$-p, :$-v, :$-w, :$...

Classes and modules have the same methods for introspecting instance variables as any other object. Class and modules also have similar methods for querying the class variables (@@these_things): p Module.methods.grep(/class_variable/) #=> [:class_variables, :class_variable_get, :remove_class_va...

It is a common practice to set application variables to an object scope. This keeps them easy to identify and distinguish from variables in other scopes. The Variables scope in a CFC is private to the CFC. When you set variables in this scope, they cannot be seen by pages that invoke the CFC. <...

MySQL allows to specify from which table the matching rows must be deleted -- remove only the employees DELETE e FROM Employees e JOIN Department d ON e.department_id = d.department_id WHERE d.name = 'Sales' -- remove employees and department DELETE e, d FROM Emp...

%storemagic stores variables and macros on IPython's database. To automatically restore stored variables at startup add this to ipython_config.py: c.StoreMagic.autorestore = True Example: In [1]: l = ['hello',10,'world'] In [2]: %store l In [3]: exit (IPython session is closed and started...

C++11 Motivational example When you have a variadic template pack in the template parameters list, like in the following code snippet: template<typename ...Args> void func(Args &&...args) { //... }; The standard library (prior to C++17) offers no direct way to write enable_if...

public static async Task<IRandomAccessStream> ConvertWriteableBitmapToRandomAccessStream(WriteableBitmap writeableBitmap) { var stream = new InMemoryRandomAccessStream(); BitmapEncoder encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.JpegEncoderId, stream); Stream pixe...

Exec sp_configure 'show advanced options' ,1 RECONFIGURE GO -- Show all configure sp_configure

Exec sp_configure 'backup compression default',1 GO RECONFIGURE;

EXEC sp_configure 'xp_cmdshell', 1 GO RECONFIGURE

Usually this means that the Master crashed and that sync_binlog was OFF. The solution is to CHANGE MASTER to POS=0 of the next binlog file (see the Master) on the Slave. The cause: The Master sends replication items to the Slave before flushing to its binlog (when sync_binlog=OFF). If the Master cr...

page.xml <Page xmlns="http://schemas.nativescript.org/tns.xsd" navigatingTo="navigatingTo"> <Repeater items="{{ myItems }}"> <Repeater.itemTemplate> <Label text="{{ title || 'Downloading...' }}" textWrap="true&quot...

page.xml <Page xmlns="http://schemas.nativescript.org/tns.xsd" navigatingTo="navigatingTo"> <ListView items="{{ myItems }}" itemTap="listViewItemTap"> <ListView.itemTemplate> <Label text="{{ title || 'Downloading.....

If your package isn't only a library, but has a piece of code that can be used either as a showcase or a standalone application when your package is installed, put that piece of code into __main__.py file. Put the __main__.py in the package_name folder. This way you will be able to run it directly ...

It is possible that the client browser does not support Javascript or have Javascript execution disabled, perhaps due to security reasons. To be able to tell users that a script is supposed to execute in the page, the <noscript> tag can be used. The content of <noscript> is displayed whe...

To concatenate the value of two or more variables into a single string and print it as the output, we need to make use of interpolation. The following Less code, #demo:after { @var1: Hello; @var2: World!!!; content: "@{var1} @{var2}"; } when compiled would set "Hello Wo...

While Runnable provides a means to wrap code to be executed in a different thread, it has a limitation in that it cannot return a result from the execution. The only way to get some return value from the execution of a Runnable is to assign the result to a variable accessible in a scope outside of t...

To make a jar, you need one or more class files. This should have a main method if it is to be run by a double click. For this example, we will use: import javax.swing.*; import java.awt.Container; public class HelloWorld { public static void main(String[] args) { JFrame f = ne...

A floating point type. Its range includes that of float. When combined with long, denotes the long double floating point type, whose range includes that of double. double area(double radius) { const double pi = 3.141592653589793; return pi*radius*radius; }