It's common practice in JavaScript to pass object literals to functions:
// JavaScript
printOptions({responsive: true});
Unfortunately we cannot pass Dart Map objects to JavaScript in these cases.
What we have to do is create a Dart object that represents the object literal and contains all of...
In this example, we use this database:
"your-project-name" : {
"users" : {
"randomUserId1" : {
"display-name" : "John Doe",
"gender" : "male"
}
"randomUserId2" :...
Note: You need to know which data referenced by getReference() first before you can completely understand this example.
There are three common method to get your data from Firebase Realtime Database:
addValueEventListener()
addListenerForSingleValueEvent()
addChildEventListener()
When w...
Step 1 - installing VirtualBox
Download and install VirtualBox according to your operating system. , it is required to run Genymotion.
Step 2 - downloading Genymotion
Go to the Genymotion download page and download Genymotion according to your operating system.
Note: you will need to create a ...
Many developers have this problem when they work on huge projects, especially if they work on some modular CMS on plugins, addons, components etc. Here is solution for safe session start where if first checked PHP version to cover all versions and on next is checked if session is started. If session...
Call this function with parameter argument as array with type 'any'. It will return you json string. Json string is used to submit array in web service call as request input parameter in Swift.
//-----------------------
let array = [["one" : 1], ["two" : 2], ["three" ...
Using the magick command (or `convert for IM 6.x users) you con convert any image format to any other. with no other arguments, as little processing as possible will be done to move from one format to the other. Simply specify your input and output files. To convert a JPEG to a PNG:
$ magick image....
This example demonstrate how to dynamically insert data into MySQL using Python Scrapy.
You do not need to edit pipelines.py file for any project.
This example can be used for all your project.
Just yield you_data_dictionary from your Spider and inside pipelines.py a query will be created automat...
Calculating the power of a given number can be done recursively as well.
Given a base number n and exponent e, we need to make sure to split the problem in chunks by decreasing the exponent e.
Theoretical Example:
2² = 2x2
2³ = 2x2x2
or, 2³ = 2² x 2In there lies the secret of our recursive al...
Physics is the natural science that involves the study of matter and its motion and behaviour through space and time, along with related concepts such as energy and force. The main goal of physics is to understand how the universe behaves. In a StackOverflow context physics usually refers to simul...
Most examples show instantiating and holding a LazySingleton object until the owning application has terminated, even if that object is no longer needed by the application. A solution to this is to implement IDisposable and set the object instance to null as follows:
public class LazySingleton : ID...
$model = Mage::getModel('catalog/product')->getCollection()
Filter based on store:
$mode->addStoreFilter($storeId)
Filter based on product type:
$mode->addAttributeToFilter('type_id', 'configurable')
$mode->addAttributeToFilter('type_id', 'simple')
Filter based on status:
$m...
A static data member of the class may be fully defined within the class definition if it is declared inline. For example, the following class may be defined in a header. Prior to C++17, it would have been necessary to provide a .cpp file to contain the definition of Foo::num_instances so that it wou...
The extern storage class specifier can modify a declaration in one of the three following ways, depending on context:
It can be used to declare a variable without defining it. Typically, this is used in a header file for a variable that will be defined in a separate implementation file.
// glo...
Since a signal handler will be called by the kernel using the C calling convention, we must tell the compiler to use the C calling convention when compiling the function.
volatile sig_atomic_t death_signal = 0;
extern "C" void cleanup(int signum) {
death_signal = signum;
}
int mai...
A C library header can usually be included into a C++ program, since most declarations are valid in both C and C++. For example, consider the following foo.h:
typedef struct Foo {
int bar;
} Foo;
Foo make_foo(int);
The definition of make_foo is separately compiled and distributed with the...
Suppose we want to write a constraint which matches a number, but approximatively. Say, you are supposed to have 95 people in a survey, but 93 or 96 will do as well. We can write a custom constraint of the form:
public class AlmostEqualToConstraint : Constraint
{
readonly int _expected;
...
