Programming Articles - Page 2018 of 2501

PHP 7 has added a new operator double question mark (??) operator. In PHP 7, the double question mark(??) operator known as Null Coalescing Operator.It returns its first operand if it exists and is not NULL; otherwise, it returns its second operand. It evaluates from left to right. Null Coalescing operator also can be used in a chain format.Let's take the below example to demonstrate the double question mark (??) operator.ExampleOutput9ExampleOutput34

In Java, it is possible to define a class inside another class, such classes are called Nested classes. We can use the access modifiers like private, public, protected or default for inner classes and default or public access modifiers for outer class.There are two types of nested classes are defined in Java.Static Nested ClassNon-Static Nested ClassStatic Nested ClassWe Can define an inner class as static, so such type of classes is called a static nested class.The nested class is defined with the static keyword, so this type of nested classes doesn’t share any relationship with the instance of an outer class.A static ... Read More

It does't matter how many lines of code you write in a program. When you want to remove or delete any elements from the Python list, you have to think about the difference between remove, del and pop in Python List and which one to useremove : remove() removes the first matching value or object, not a specific indexing. lets say list.remove(value)Examplelist=[10, 20, 30, 40] list.remove(30) print(list)Output[10, 20, 40]del : del removes the item at a specific index. lets say del list[index]Examplelist = [10, 20, 30, 40, 55] del list[1] print(list)Output[10, 30, 40, 55]pop : pop removes the item at a specific index and returns ... Read More

Python uses a mechanism, which is known as "Call-by-Object", sometimes also called "Call by Object Reference" or "Call by Sharing"If you pass immutable arguments like integers, strings or tuples to a function, the passing acts like Call-by-value. It's different, if we pass mutable arguments.All parameters (arguments) in the Python language are passed by reference. It means if you change what a parameter refers to within a function, the change also reflects back in the calling function.Examplestudent={'Archana':28, 'krishna':25, 'Ramesh':32, 'vineeth':25} def test(student):    new={'alok':30, 'Nevadan':28}    student.update(new)    print("Inside the function", student)    return test(student) print("outside the function:", student)OutputInside the function ... Read More

We can solved the above problem using array_walk_recursive() function.array_walk_recursive()   is an inbuilt PHP function. This function converts array to XML document where keys of the array are converted into values and values of the array are converted into the element of XML.Let' demonstrate with a simple example.ExampleOutput alex account michigan NoteIf errors message display like PHP Fatal error: Uncaught Error: Class 'SimpleXMLElement' not found in then simply install php-xml, php-simplexml packages.

In this article, we will learn to validate an email with PHP regular expression. We will learn different methods to validate email address in PHP.Method1The function preg_match() checks the input matching with patterns using regular expressions.Example Live DemoOutputValid email address.In the above example PHP preg_match() function has been used to search string for a pattern and PHP ternary operator has been used to return the true or false value based on the preg_match return.Method 2We will discuss email validation using filter_var() method.Example Live DemoOutputpattrick@tutorialspoint.com is a valid email addressRead More

Output Buffering is a method to tell the PHP engine to hold the output data before sending it to the browser. As we know PHP sent the output data to the browser in pieces, but if we utilize the output buffering mechanism, the output data is stored in a variable and sent to the browser as one piece at the end of the script.ExampleLet's demonstrate with a simple example. Live DemoOutputstring(5) "Hello" string(20) "HelloTutorials Point"ExplanationIn the above example ob_get_contents() grabs all of the data gathered since we called ob_start, i.e. everything in the buffer. After that send the output data at ... Read More

We can remove non-alphanumeric characters from the string with preg_replace() function in PHP. The preg_replace() function is an inbuilt function in PHP which is used to perform a regular expression for search and replace the content.syntaxpreg_replace(pattern, replacement, subject, limit, count )Let's discuss the parameters of the function underneath.patternThis parameter contains the pattern to search for.replacementIt is a mandatory parameter. This parameter may contain a string or an array with strings to replace.subjectThe string or an array with strings to search and replace.limitThe maximum possible replacements for each pattern in each subject stringcountThis is an optional parameter, if specified then this ... Read More

No, we cannot declare a top-level class as private or protected. It can be either public or default (no modifier). If it does not have a modifier, it is supposed to have a default access.Syntax// A top level class    public class TopLevelClassTest {       // Class body }If a top-level class is declared as private the compiler will complain that the modifier private is not allowed here. This means that a top-level class cannot be a private, the same can be applied to protected access specifier also.Protected means that the member can be accessed by any class in the same ... Read More

Yes, we can access the local final variables using the method local inner class because the final variables are stored on the heap and live as long as the method local inner class object may live.Method Local Inner ClassA local inner class instance can be delivered as an argument and retrieved from the methods and it is available inside a valid scope.The only limitation in method local inner class is that a local parameter can be executed only when it is defined as final.The method executing the local parameters can be called after the execution of the method, within which the local inner ... Read More