Tutorial by Examples: s

To repeat a function indefinitely, setTimeout can be called recursively: function repeatingFunc() { console.log("It's been 5 seconds. Execute the function again."); setTimeout(repeatingFunc, 5000); } setTimeout(repeatingFunc, 5000); Unlike setInterval, this ensures that t...

Dim input as String = Console.ReadLine() Console.ReadLine() will read the console input from the user, up until the next newline is detected (usually upon pressing the Enter or Return key). Code execution is paused in the current thread until a newline is provided. Afterwards, the next line of co...

Dim x As Int32 = 128 Console.WriteLine(x) ' Variable ' Console.WriteLine(3) ' Integer ' Console.WriteLine(3.14159) ' Floating-point number ' Console.WriteLine("Hello, world") ' String ' Console.WriteLine(myObject) ' Outputs the value from calling myObject.ToString() The Console.Wri...

Dim x As Int32 = 128 Console.Write(x) ' Variable ' Console.Write(3) ' Integer ' Console.Write(3.14159) ' Floating-point number ' Console.Write("Hello, world") ' String ' The Console.Write() method is identical to the Console.WriteLine() method except that it prints the given argumen...

Libraries other than jQuery may also use $ as an alias. This can cause interference between those libraries and jQuery. To release $ for use with other libraries: jQuery.noConflict(); After calling this function, $ is no longer an alias for jQuery. However, you can still use the variable jQuery...

Create a snapshot of a whole database: mysqldump [options] db_name > filename.sql Create a snapshot of multiple databases: mysqldump [options] --databases db_name1 db_name2 ... > filename.sql mysqldump [options] --all-databases > filename.sql Create a snapshot of one or more tables...

> mysqldump -u username -p [other options] Enter password: If you need to specify the password on the command line (e.g. in a script), you can add it after the -p option without a space: > mysqldump -u username -ppassword [other options] If you password contains spaces or special chara...

mysql [options] db_name < filename.sql Note that: db_name needs to be an existing database; your authenticated user has sufficient privileges to execute all the commands inside your filename.sql; The file extension .sql is fully a matter of style. Any extension would work. You cannot spe...

c++14 Lambda functions can take arguments of arbitrary types. This allows a lambda to be more generic: auto twice = [](auto x){ return x+x; }; int i = twice(2); // i == 4 std::string s = twice("hello"); // s == "hellohello" This is implemented in C++ by making the closur...

If a lambda's capture list is empty, then the lambda has an implicit conversion to a function pointer that takes the same arguments and returns the same return type: auto sorter = [](int lhs, int rhs) -> bool {return lhs < rhs;}; using func_ptr = bool(*)(int, int); func_ptr sorter_func = ...

performance.now() returns a precise timestamp: The number of milliseconds, including microseconds, since the current web page started to load. More generally, it returns the time elapsed since the performanceTiming.navigationStart event. t = performance.now(); For example, in a web browser's ma...

Date.now() returns the number of whole milliseconds that have elapsed since 1 January 1970 00:00:00 UTC. t = Date.now(); For example, Date.now() returns 1461069314 if it was called on 19 April 2016 at 12:35:14 GMT.

In older browsers where Date.now() is unavailable, use (new Date()).getTime() instead: t = (new Date()).getTime(); Or, to provide a Date.now() function for use in older browsers, use this polyfill: if (!Date.now) { Date.now = function now() { return new Date().getTime(); }; }

To authenticate to Watson services, you need credentials for each service that you plan to use. Depending on the service, you will need to pass a username and password with Basic Authentication, or you will need to pass an API key in a parameter for each request you make. How to get credentials for...

For any file operations, you will need the filesystem module: const fs = require('fs'); Reading a String fs.readFileSync behaves similarly to fs.readFile, but does not take a callback as it completes synchronously and therefore blocks the main thread. Most node.js developers prefer the asynch...

C++11 A std::unique_ptr is a class template that manages the lifetime of a dynamically stored object. Unlike for std::shared_ptr, the dynamic object is owned by only one instance of a std::unique_ptr at any time, // Creates a dynamic int with value of 20 owned by a unique pointer std::unique_pt...

If you need to create a JSONObject and put data in it, consider the following example: // Create a new javax.json.JSONObject instance. JSONObject first = new JSONObject(); first.put("foo", "bar"); first.put("temperature", 21.5); first.put("year", 2016);...

If you need to get data from a JSONObject, consider the following example: String json = "{\"foo\":\"bar\",\"temperature\":21.5,\"year\":2016,\"message\":{\"Hello\":\"world\"},\"months\":[\"January\",\&qu...

JSONObject and JSONArray have a few methods that are very useful while dealing with a possibility that a value your are trying to get does not exist or is of another type. JSONObject obj = new JSONObject(); obj.putString("foo", "bar"); // For existing properties of the corre...

Overview Attribute selectors can be used with various types of operators that change the selection criteria accordingly. They select an element using the presence of a given attribute or attribute value. Selector(1)Matched elementSelects elements...CSS Version[attr]<div attr>With attribute a...