The function func_num_args() is used to give the number of parameters passed into a function.
How can we define a variable accessible in functions of a PHP script?
This feature is possible using the global keyword.
How is it possible to return a value from a function?
A function returns a value using the instruction 'return $value;'.
What is the most convenient hashing method to be used to hash passwords?
It is preferable to use crypt() which natively supports several hashing algorithms or the function hash() which supports more variants than crypt() rather than using the common hashing algorithms such as md5, sha1 or sha256 because they are conceived to be fast. Hence, hashing passwords with these algorithms can create vulnerability.
what is the difference between for and foreach?
for is expressed as follows:
for (expr1; expr2; expr3)
statement
The first expression is executed once at the beginning. In each iteration, expr2 is evaluated. If it is TRUE, the loop continues, and the statements inside for are executed. If it evaluates to FALSE, the execution of the loop ends. expr3 is tested at the end of each iteration.
However, foreach provides an easy way to iterate over arrays, and it is only used with arrays and objects.
Explain how you can update Memcached when you make changes to PHP?
When PHP changes you can update Memcached by
Clearing the Cache proactively: Clearing the cache when an insert or update is made
Resetting the Cache: It is similar to the first method but rather than just deleting the keys and waiting for the next request for the data to refresh the cache, reset the values after the insert or update.
Which cryptographic extension provide generation and verification of digital signatures?
The PHP-OpenSSL extension provides several cryptographic operations including generation and verification of digital signatures.
How is a constant defined in a PHP script?
The define() directive lets us defining a constant as follows:
define ("ACONSTANT", 123);
How can you pass a variable by reference?
To be able to pass a variable by reference, we use an ampersand in front of it, as follows $var1 = &$var2
Will a comparison of an integer 12 and a string "13" work in PHP?
"13" and 12 can be compared in PHP since it casts everything to the integer type.
If the variable $var1 is set to 10 and the $var2 is set to the character var1, what's the value of $$var2?
$$var2 contains the value 10.
 |
| CDW Most Frequently Asked Latest PHP Interview Questions Answers |
What does accessing a class via :: means?
:: is used to access static methods that do not require object initialization.
In PHP, objects are they passed by value or by reference?
In PHP, objects passed by value.
Are Parent constructors called implicitly inside a class constructor?
No, a parent constructor have to be called explicitly as follows:
parent::constructor($value)
What's the difference between __sleep and __wakeup?
__sleep returns the array of all the variables that need to be saved, while __wakeup retrieves them.
What is faster?
1- Combining two variables as follows:
$variable1 = 'Hello ';
$variable2 = 'World';
$variable3 = $variable1.$variable2;
Or
2- $variable3 = "$variable1$variable2";
$variable3 will contain "Hello World". The first code is faster than the second code especially for large large sets of data.
What does $_COOKIE mean?
$_COOKIE is an associative array of variables sent to the current PHP script using the HTTP Cookies.
What does the scope of variables mean?
The scope of a variable is the context within which it is defined. For the most part, all PHP variables only have a single scope. This single scope spans included and required files as well.
Is it possible to submit a form with a dedicated button?
It is possible to use the document.form.submit() function to submit the form. For example: <input type=button value="SUBMIT" onClick="document.form.submit()">
What is the difference between ereg_replace() and eregi_replace()?
The function eregi_replace() is identical to the function ereg_replace() except that it ignores case distinction when matching alphabetic characters.
Is it possible to protect special characters in a query string?
Yes, we use the urlencode() function to be able to protect special characters.
What are the three classes of errors that can occur in PHP?
The three basic classes of errors are notices (non-critical), warnings (serious errors) and fatal errors (critical errors).
What is the difference between characters \034 and \x34?
\034 is octal 34 and \x34 is hex 34.
How can we pass the variable through the navigation between the pages?
It is possible to pass the variables between the PHP pages using sessions, cookies or hidden form fields.
Is it possible to extend the execution time of a PHP script?
The use of the set_time_limit(int seconds) enables us to extend the execution time of a PHP script. The default limit is 30 seconds.
Is it possible to destroy a cookie?
Yes, it is possible by setting the cookie with a past expiration time.
What is the default session time in PHP?
The default session time in php is until the closing of the browser
Is it possible to use COM component in PHP?
Yes, it's possible to integrate (Distributed) Component Object Model components ((D)COM) in PHP scripts which is provided as a framework.
Explain whether it is possible to share a single instance of a Memcache between multiple PHP projects?
Yes, it is possible to share a single instance of Memcache between multiple projects. Memcache is a memory store space, and you can run memcache on one or more servers. You can also configure your client to speak to a particular set of instances. So, you can run two different Memcache processes on the same host and yet they are completely independent. Unless, if you have partitioned your data, then it becomes necessary to know from which instance to get the data from or to put into.
what the difference between the 'BITWISE AND' operator and the 'LOGICAL AND' operator?
$a and $b: TRUE if both $a and $b are TRUE.
$a & $b: Bits that are set in both $a and $b are set.
What are the two main string operators?
The first is the concatenation operator ('.'), which returns the concatenation of its right and left arguments. The second is ('.='), which appends the argument on the right to the argument on the left.
What does the array operator '===' means?
$a === $b TRUE if $a and $b have the same key/value pairs in the same order and of the same types.
What is the differences between $a != $b and $a !== $b?
!= means inequality (TRUE if $a is not equal to $b) and !== means non-identity (TRUE if $a is not identical to $b).
what is the definition of a session?
A session is a logical object enabling us to preserve temporary data across multiple PHP pages.
How to initiate a session in PHP?
The use of the function session_start() lets us activating a session.