Senior PHP Programmer

All objects in PHP have Constructor and Destructor methods built-in. The Constructor method is called immediately after a new instance of the class is being created, and it's used to initialize class properties. The Destructor method takes no parameters.

Understanding these two in PHP means that the candidate knows the very basics of OOP in PHP.

PHP script using command line can be executed using SAPI (Server Application programming Interface). Using SAPI Command Line Interface the PHP code can be passed to execute directly

Example:

Php -r 'print_r(get_defined_constanrs());'

From a shell, php -v will display whether the SAPI is CLI or CGI

Do not output anything to the browser before using code that modifies the HTTP headers. Once you call echo or any other code that clears the buffer you can no longer set cookies or headers. That is also true for error messages, so if an error happens before you use the header command and the INI directive display_errors is set then that will also cause that error to show.

Yes PHP is a case sensitive language

_FUNCTION_ − The function name. (Added in PHP 4.3.0) As of PHP 5 this constant returns the function name as it was declared (case-sensitive). In PHP 4 its value is always lowercased.

Multidimensional array − An array containing one or more arrays and values are accessed using multiple indices.

NULL is a special type that only has one value: NULL. To give a variable the NULL value, simply assign it like this −

$my_var = NULL;

The special constant NULL is capitalized by convention, but actually it is case insensitive; you could just as well have typed −

$my_var = null;

A variable that has been assigned NULL has the following properties:

It evaluates to FALSE in a Boolean context.

It returns FALSE when tested with IsSet() function.

If the file is not found by require(), it will cause a fatal error and halt the execution of the script. If the file is not found by include(), a warning will be issued, but execution will continue.

for, while, do while and foreach (NB: You should learn its usage)

The PHP default variable $_PHP_SELF is used for the PHP script name and when you click "submit" button then same PHP script will be called.

If there is any problem in loading a file then the require() function generates a fatal error and halt the execution of the script whereas include() function generates a warning but the script will continue execution.

The strpos() function is used to search for a string or character within a string. If a match is found in the string, this function will return the position of the first match. If no match is found, it will return FALSE. Let's see if we can find the string "world" in our string −

<?php

echo strpos("Hello world!","world");

?>

This will produce following result −

6

The files's length can be found using the filesize() function which takes the file name as its argument and returns the size of the file expressed in bytes.

Rules for naming a variable are following −

Variable names must begin with a letter or underscore character.

A variable name can consist of numbers, letters, underscores but you cannot use characters like + , - , % , ( , ) . & , etc

Final keywords indicates that the class or method cannot be extended.

session_id() function returns the session id for the current session.

The following code can be used for it,

header("Location: http://www.rendc.org/");

break terminates the for loop or switch statement and transfers execution to the statement immediately following the for loop or switch.

We can send 1024 bytes using GET method but POST method can transfer large amount of data and POST is the secure method than GET method .