According to my experience here I am sharing top 35 frequently asked PHP interview questions and answers for 1 year experiences PHP developer, This list of PHP interview questions and answers will be helpful for PHP experience developer.
Question #6: How to get the location of php.ini?
You can get the location of php.ini by using <?php phpinfo(); ?> code.
Question #8: How to identify server IP address in PHP?
you can identify server IP address by using $_SERVER['SERVER_ADDR'];
Question #9: What is use of header() function in PHP ?
Header() function is mostly used to Redirect from one page to another -
Question #1 - What is the difference between $message and $$message?
They are both variables But $message is a variable with a fixed name. $$message is a variable whose name is stored in $message. For example, if $message contains "var", $$message is the same as $var.
Question #2 - How to include a file to a php page?
We include a file using "include('filepath.php') " or "require('filepath.php')" function with file path as its parameter.
Question #3 - What's the difference between include and require?
If the file is not found by require(), it will cause a fatal error and stop the execution of the script. If the file is not found by include(), a warning will be generate, but execution will continue.
Question #4 - Differences between GET and POST methods ?
We can only send 1024 bytes through GET method but by POST method can transfer large amount of data and POST is also a secure method than GET method .
Question #5 - require_once(), require(), include().What is difference between them?
require() includes and evaluates a specific file, while require_once() does that only if it has not been included before (on the same page). So, require_once() is recommended to use when you want to include a file where you have a lot of functions for example. This way you make sure you don't include the file more times and you will not get the "function re-declared" error.
You can get the location of php.ini by using <?php phpinfo(); ?> code.
Question #7 - Differences between GET and POST methods ?
We can only send 1024 bytes through GET method but by POST method can transfer large amount of data and POST is also a secure method than GET method .
you can identify server IP address by using $_SERVER['SERVER_ADDR'];
Question #9: What is use of header() function in PHP ?
Header() function is mostly used to Redirect from one page to another -
<?php header("Location:page.php"); ?>
Question #10 - What type of inheritance supports by PHP?
There are following type of inheritance
- Single Inheritance - Support by PHP
- Multiple Inheritance - Not support
- Hierarchical Inheritance - Support by PHP
- Multilevel Inheritance - Support by PHP
Question #11 - What is the use of 'print' in php?
Print commonly used to print text on screen like echo but print has a return type. you can use with out parentheses with its argument list.
Example
Example
print('50 PHP Interview questions');
print 'Job Interview questions ';
Question #12 - What is the difference between Session and Cookie?
Both are used to store user information on server. The main difference between sessions and cookies is that sessions are stored on the server, and cookies are stored on the user's computers in the text file format. Cookies can't hold multiple variable while session can hold multiple variables..We can set expiry for a cookie,The session only remains active as long as the browser is open.Users do not have access to the data you stored in Session,Since it is stored in the server.Session is mainly used for login/logout purpose while cookies using for user activity tracking
Question #13 - How to set cookies in PHP?
We can set cookies like Setcookie("user", "ram", time()+3600);
Question #14 - How to create a session? How to set a value in session ? How to Remove data from a session?
Create session : session_start();
Set value into session : $_SESSION['USER_ID']=1;
Set value into session : $_SESSION['USER_ID']=1;
Remove data from a session : unset($_SESSION['USER_ID'];
Question #15 - What are different type of sorting functions in PHP?
sort() - sort arrays in ascending order.
asort() - sort associative arrays in ascending order, according to the value.
ksort() - sort associative arrays in ascending order, according to the key.
arsort() - sort associative arrays in descending order, according to the value.
rsort() - sort arrays in descending order.
krsort() - sort associative arrays in descending order, according to the key.
array_multisort() - sort the multi dimension array.
asort() - sort associative arrays in ascending order, according to the value.
ksort() - sort associative arrays in ascending order, according to the key.
arsort() - sort associative arrays in descending order, according to the value.
rsort() - sort arrays in descending order.
krsort() - sort associative arrays in descending order, according to the key.
array_multisort() - sort the multi dimension array.
Question #16 - What is the use of explode() function ?
This function is used to split a string into an array. Syntax : array explode( string $delimiter , string $string [, int $limit ] );
Question #17 - What is the difference between explode() and split() functions?
Split function splits string into array by regular expression. Explode splits a string into array by string.
Both function are used to breaks a string into an array, the difference is that Split() function breaks split string into an array by regular expression and explode() splits a string into an array by string. explode() is faster than split() because it does not match the string based on regular expression.
Question #18 - What is the use of mysql_real_escape_string() function?
mysql_real_escape_string() function mainly used to escapes special characters in a string for use in an SQL statement
Question #19 - How to redirect a page in php?
we can redirect a page by using header("Location:index.php"); function.
Question #20 - How to find the length of a string?
we can use strlen() function to find the length of a string
Question #21 - what is the use of isset() in php?
isset() function is used to ensure if a variable is set and is not NULL
Question #22 - How to delete a file from the system
we can delete a file by using Unlink() function in php.
Question #23 - what is the difference between javascript and PHP ?
Commonly JavaScript known as Client side scripting language while PHP is a server side scripting language.
Question #24 - What is MIME?
Full form of MIME is "Multi-purpose Internet Mail Extensions".
It is extension of e-mail protocol helps to exchanges the different kids of data files over the internet.
Data files may be audio, video, images, application programs and ASCII etc.
Question #25 - How to create a mysql connection?
we can create connection by using function mysql_connect(hostname,username,password,database);
Question #26 - How to select a database?
we can select database by using mysql_select_db($db_name); function and we can also select a database by using function mysql_query('use databaseName');
Question #27 - How To Select The nth Highest Record In MySQL?
The query to get the nth highest record is as follows:
Question #29: What type of inheritance does not support by PHP ?
Only Multiple Inheritance does not support by PHP.
Question #30: What is PEAR?
PEAR stands for PHP Extension and Application Repository. PEAR is a framework and repository for re-usable PHP components.
Question #31: How to get duplicate values from array?
you can get duplicate values from an array by using array_diff_assoc($arr, $arr_unique); for an example :
It will return :
Array(
[1] => anil
[2] => sunita
)
SELECT
*
FROM
table_name
ORDER BY column_name DESC
LIMIT n - 1, 1;
Question #28 - What is the difference between mysql_fetch_array() and mysql_fetch_assoc() ?
mysql_fetch_assoc() function Fetch data as an associative array, While mysql_fetch_array() fetches data as an associative array, a numeric array, or both
Only Multiple Inheritance does not support by PHP.
Question #30: What is PEAR?
PEAR stands for PHP Extension and Application Repository. PEAR is a framework and repository for re-usable PHP components.
Question #31: How to get duplicate values from array?
you can get duplicate values from an array by using array_diff_assoc($arr, $arr_unique); for an example :
<php$arr = ('anil','anil','sonia','monica','sunita','sunita','raj');$arr_unique = array_unique($arr);$arr_duplicates = array_diff_assoc($arr, $arr_unique);print_r($arr_duplicates);?>
It will return :
Array(
[1] => anil
[2] => sunita
)
Question #32 - What is CSS?
CSS known as cascading Style Sheet. It is a best technique to style and present HTML.
Question #33 - What are the differences between ID and class in CSS?
ID is used to identify one element , while a class is used to identify more than one element.
Question #34 - How stop the execution of a php scrip ?
We mostly use exit() function to stop the execution of a page
Question #35 - How to strip whitespace (or other characters) from the beginning and end of a string ?
We can use trim() function to remove whitespaces or other predefined characters from both sides of a string.
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