R is a programming language. R is often used for statistical computing and graphical presentation to analyze and visualize data. Start learning R now ».
The slice () method returns selected elements in an array, as a new array. The slice () method selects from a given start , up to a (not inclusive) given end. The slice () method does not change the o
The slice () method returns the extracted part in a new string. The slice () method does not change the original string. The start and end parameters specifies the part of the string to extract. The f
JavaScript const variables must be assigned a value when they are declared: Meaning: An array declared with const must be initialized when it is declared. Using const without initializing the array is
When to use JavaScript const? Always declare a variable with const when you know that the value should not be changed. Use const when you declare: A new Array A new Object A new Function A new RegExp
SQL Server. The SQL Server ISNULL () function lets you return an alternative value when an expression is NULL: SELECT ProductName, UnitPrice * (UnitsInStock + ISNULL (UnitsOnOrder, 0)) FROM Products;
The IF () function returns a value if a condition is TRUE, or another value if a condition is FALSE. Syntax IF ( condition, value_if_true, value_if_false) Parameter Values Technical Details Works in:
Java is an object oriented language and some concepts may be new. Take breaks when needed, and go over the examples as many times as needed. Java Exercises Test Yourself With Exercises Exercise: Inser
OOP stands for Object-Oriented Programming. Procedural programming is about writing procedures or methods that perform operations on the data, while object-oriented programming is about creating objec
JavaScript objects are containers for named values called properties. Object Methods Objects can also have methods. Methods are actions that can be performed on objects. Methods are stored in properti
Background Cover. If you want the background image to cover the entire element, you can set the background-size property to cover.. Also, to make sure the entire element is always covered, set the bac
The background-position property sets the starting position of a background image. Tip: By default, a background-image is placed at the top-left corner of an element, and repeated both vertically and
Syntax. do {. // code block to be executed. } while (condition); The example below uses a do/while loop. The loop will always be executed at least once, even if the condition is false, because the cod
The while loop loops through a block of code as long as a specified condition is true: Syntax while (condition) { // code block to be executed } In the example below, the code in the loop will run, ov
Definition and Usage. The justify-content property aligns the flexible container's items when the items do not use all available space on the main-axis (horizontally). Tip: Use the align-items propert
The LEFT JOIN keyword returns all records from the left table (table1), and the matching records from the right table (table2). The result is 0 records from the right side, if there is no match. LEFT
Example. This example shows a bad combination of text and background image. The text is hardly readable: body {. background-image: url ("bgdesert.jpg"); } Try it Yourself ». Note: When using a backgro
Set the background color and text color of headings (with CSS): Hello World Hello World Try it Yourself » Example Set t
The tag is an empty tag which means that it has no end tag. Tips and Notes. Note: Use the tag to enter line breaks, not to add space between paragraphs. Browser Support. Element Yes: Ye
The HAVING clause was added to SQL because the WHERE keyword cannot be used with aggregate functions. HAVING Syntax SELECT column_name (s) FROM table_name WHERE condition GROUP BY column_name (s) HAVI
The GROUP BY statement is often used with aggregate functions ( COUNT (), MAX (), MIN (), SUM (), AVG ()) to group the result-set by one or more columns. GROUP BY Syntax SELECT column_name (s) FROM ta
Three Ways to Insert CSS There are three ways of inserting a style sheet: External CSS Internal CSS Inline CSS External CSS With an external style sheet, you can change the look of an entire website b
CSS can be added to HTML documents in 3 ways: Inline - by using the style attribute inside HTML elements Internal - by using a element in the section External - by using a elemen
Example 1 Remove spaces with trim (): let text = " Hello World! "; let result = text.trim(); Try it Yourself » Remove spaces with replace () using a regular expression: let text = " Hello World! "; le
Java String trim () Method String Methods Example Remove whitespace from both sides of a string: String myStr = " Hello World! "; System.out.println(myStr); System.out.println(myStr.trim()); Try it Yo
A Boolean expression is a Java expression that returns a Boolean value: true or false. This is useful when we want to compare values to find answers. For example, you can use a comparison operator, su
The split () method splits a string into a list. You can specify the separator, default separator is any whitespace. Note: When maxsplit is specified, the list will contain the specified number of ele