Tutorial by Examples: at

Starting with Java 8, you can use lambda expressions & predicates. Example: Use a lambda expressions & a predicate to get a certain value from a list. In this example every person will be printed out with the fact if they are 18 and older or not. Person Class: public class Person { p...

A DataFrame can be created from a list of dictionaries. Keys are used as column names. import pandas as pd L = [{'Name': 'John', 'Last Name': 'Smith'}, {'Name': 'Mary', 'Last Name': 'Wood'}] pd.DataFrame(L) # Output: Last Name Name # 0 Smith John # 1 Wood Mary Missin...

Shall the property value's assignment be executed before or after the class' constructor? public class TestClass { public int TestProperty { get; set; } = 2; public TestClass() { if (TestProperty == 1) { Console.WriteLine("Shall this be e...

Using parameters passed by reference An event may define a ByRef parameter meant to be returned to the caller: Public Event BeforeSomething(ByRef cancel As Boolean) Public Event AfterSomething() Public Sub DoSomething() Dim cancel As Boolean RaiseEvent BeforeSomething(cancel) If...

You can use the filter operator to filter out items from the values stream based on a result of a predicate method. In other words, the items passing from the Observer to the Subscriber will be discarded based on the Function you pass filter, if the function returns false for a certain value, that ...

You can use the map operator to map the values of a stream to different values based on the outcome for each value from the function passed to map. The outcome stream is a new copy and will not modify the provided stream of values, the result stream will have the same length of the input stream but ...

CREATE TYPE dbo.Ids as TABLE ( Id int PRIMARY KEY )

CREATE TYPE MyComplexType as TABLE ( Id int, Name varchar(10) )

CREATE TYPE MyUniqueNamesType as TABLE ( FirstName varchar(10), LastName varchar(10), UNIQUE (FirstName,LastName) ) Note: constraints in user defined table types can not be named.

CREATE TYPE MyUniqueNamesType as TABLE ( FirstName varchar(10), LastName varchar(10), CreateDate datetime default GETDATE() PRIMARY KEY (FirstName,LastName) )

This example finds an array of approximately evenly spaced points along a quadratic curve. It decomposes Path segments created with context.quadraticCurveTo into points along that curve. // Return: an array of approximately evenly spaced points along a Quadratic curve // // Attribution: Stackove...

This example finds an array of approximately evenly spaced points along an entire Path. It decomposes all Path segments created with context.lineTo, context.quadraticCurveTo and/or context.bezierCurveTo into points along that Path. Usage // Path related variables var A={x:50,y:100}; var B={x:12...

Sonarqube uses database for storing its results and analysis. You can install MySQL for example and run it using mysql -u root -p and then run the following queries to set up the database tables. CREATE DATABASE sonar CHARACTER SET utf8 COLLATE utf8_general_ci; CREATE USER 'sonar' IDENTIFIED BY 's...

Interpolation means that Perl interpreter will substitute the values of variables for their name and some symbols (which are impossible or difficult to type in directly) for special sequences of characters (it is also known as escaping). The most important distinction is between single and double qu...

Perl interpolates variable names: my $name = 'Paul'; print "Hello, $name!\n"; # Hello, Paul! my @char = ('a', 'b', 'c'); print "$char[1]\n"; # b my %map = (a => 125, b => 1080, c => 11); print "$map{a}\n"; # 125 Arrays may be interpolated as a whol...

First, define a used defined table type to use: CREATE TYPE names as TABLE ( FirstName varchar(10), LastName varchar(10) ) GO Create the stored procedure: CREATE PROCEDURE prInsertNames ( @Names dbo.Names READONLY -- Note: You must specify the READONLY ) AS INSERT INTO d...

The "right-left" rule is a completely regular rule for deciphering C declarations. It can also be useful in creating them. Read the symbols as you encounter them in the declaration... * as "pointer to" - always on the left side [] as "array of" ...

A goto statement transfers control to the statement with the corresponding label within the same function. Executing the goto statement must not cause any variables to come into scope that were not already in scope at the point of the goto. for example see the standard library source code: https:/...

WeakMap object allows you to store key/value pairs. The difference from Map is that keys must be objects and are weakly referenced. This means that if there aren't any other strong references to the key, the element in WeakMap can be removed by garbage collector. WeakMap constructor has an optional...

To get a value associated to the key, use the .get() method. If there's no value associated to the key, it returns undefined. const obj1 = {}, obj2 = {}; const weakmap = new WeakMap([[obj1, 7]]); console.log(weakmap.get(obj1)); // 7 console.log(weakmap.get(obj2)); // undefined