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Advanced PHP Interview Questions

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This article will show you the advance interview questions asked in any interview. We would advice you to read this blog because it provides helpful questions for fresher and experience as well.

Before getting to this blog, you need to ensure the basic. Checkout the PHP Interview Questions For Freshers

Let's see the list of top Advance Level PHP Interview Question:

Q1: How Can We Get The IP Address Of The Client?

This question has many choices and can show how playful and creative the candidate is. $_SERVER ["REMOTE_ADDR"]; is the simplest solution, but candidates can write an x-line script for this question.

Q2: What’s The Difference Between Unset() And Unlink()?

The unset() function unsets a variable while unlink() deletes a file we pass to it from the file system.

Q3: What Are The Main Error Types In PHP And How Do They Differ?

In PHP there are 3 main type of errors:

  • Notices – A simple, non-critical error that occurred while running the script. An example of a Notice is access to an undefined variable.
  • Warnings – This is a more important error than the Notice, but the script will continue to run. As an example, include () a file that does not exist.
  • Fatal – When this type of error occurs, script execution is aborted. A fatal example of a fatal error is accessing a property of a non-existent object or require() a non-existent file.
Q4: What Are The Difference Between Array_merge() And Array_combine()?

array_combine() : Used to create a new array, using the key of one array as the key and the value of another array as the value.

$name=array("John","Smith");
$age=array("20","22");
Array ( [John] => 20 [Smith] => 22)

array_merge() : Merges one or more arrays so that the values in the array are added to the end of the first array. If the array has the same string key, the next value overrides the previous value for that key.

$a=array("apple","banana");
$b=array("red","yellow");
Array ( [0] => red [1] => green [2] => blue [3] => yellow )
Q5: How Can You Enable Error Reporting In PHP?

Check if "display_errors" is "on" in php.ini or declare "ini_set('display_errors', 1) "in the script. Then add "error_reporting(E_ALL)" to your code to display all kinds of error messages while the script is running.

ini_set('display_errors', 1);
ini_set('display_startup_errors', 1);
error_reporting(E_ALL);
Q6: What Are Traits?

Traits are a mechanism that allows you to write reusable code in languages such as PHP that do not support multiple inheritance. Traits cannot be instantiated independently.

It is important to understand the powerful features of the language that developers are working on, and the trait is one of those features.

Q7: Can The Value Of A Constant Change During The Script’s Execution?

No, you can't change the value of a constant declared while PHP is running.

Q8: Can You Extend A Final Defined Class?

No, you can't extend the Final defined class. A Final class or method declaration prevents child class or method overriding.

Q9: What Are The __construct() And __destruct() Methods In A PHP Class?

All PHP objects have built-in constructor and destructor methods. Constructor methods are called immediately after a new instance of the class is created and are used to initialize the properties of the class. The Destructor method requires no parameters.

Q10: All PHP Objects Have Built-In Const

Private - Displayed only in your own class.

Public - Viewed by other code accessing the class.

Protected - Appears only to the parent and class of the class that extends the current class.

Q11: What Are Getters And Setters And Why Are They Important?

Getters and setters are a way to define or get the value of a variable (usually a private variable). As the name implies, getter methods are techniques for getting or recovering the value of an object.

Q12: Explain How We Handle Exceptions In PHP?

If an exception is thrown, the code following the statement will not be executed and PHP will try to find the first matching catch block. If the exception is not caught, a PHP fatal error with an "uncaught exception" will be thrown. Exceptions can be thrown and caught in PHP.

Q13: How To Download Files From An External Server With Code In PHP?

This can be done in a variety of ways. If allow_url_fopen is set to true: You can use cURL() to download images or files from an external server, but in this case curl is activated on both servers. You can also do this with file_put_contents().

Q14: Why Do We Use Extract()?

The extract() function imports variables from an array into a local symbol table. This function uses the array key as the variable name and the value as the variable value.

Q15: What Exactly Is The The Difference Between Array_map, Array_walk And Array_filter?

array_map : Applies a callback to the elements of the specified array. A callback function that is executed for each element of each array.

array_walk : Applies user-defined functions to all elements of the array. Applies a user-defined callback function to all elements of an array. array_walk () is not affected by the array's internal array pointer. array_walk () walks the entire array, regardless of the pointer position.

array_filter : Uses a callback function to filter the elements of the array. Iterate over each value in the array and pass it to the callback function. If the callback function returns true, the current value is returned from the array to the resulting array.

Q16: How To Remove HTML Tags From Data In PHP?

You can use strip_tags () to strip HTML tags from your PHP data. The strip_tags () function strips strings from HTML, XML, and PHP tags.

strip_tags(string, allow);

The first parameter is required. It specifies the string to check.

The second parameter is optional. It specifies allowable tags. Mention tags will not be removed.

Q17: What Is The Difference Between REST And Soap?

SOAP stands for Simple Object Access Protocol and REST stands for Representation State Transfer.

SOAP is a protocol and the the Rest is architectural style. SOAP only allows XML data formats, while REST allows other data formats such as plain text, HTML, XML, and JSON.

SOAP requires more bandwidth and resources than REST. Therefore, avoid using SOAP when bandwidth is minimal.

Q18: What Is A Composer?

This is an application package manager for the PHP programming language that provides a standard format for managing PHP software dependencies. The composer was developed by Nils Adderman and Jordi Bogiano, who continue to lead the project. The composer is easy to use and the installation can be done from the command line.

You can download it directly from https://getcomposer.org/download. You can use composer to solve the following problems:

  • Resolution of dependency for PHP packages
  • To keep all packages up to date
  • The solution is automatic loading of PHP packages
Q19: What Are The Differences Between Die() And Exit() Functions In PHP?

There is no difference, they are the same. The only advantage of choosing die() over exit() may be that you can save time typing extra characters.

Q20: How Many Items Are Available In The $_FILES Array?

$_FILES[‘userfile’][‘error’]

$_FILES[‘userfile’][‘name’]

$_FILES[‘userfile’][‘size’]

$_FILES[‘userfile’][‘tmp_name’]

$_FILES[‘userfile’][‘type’]

are the five items in the array.