Complete PHP with mysql interview Questions with answers-- Asked at different competitive exams
Free Online test your knowledge on php and mysql programming exams. Each questions immediate answer or explanation given below, just click View answer button and also have option of Hide Answer button to hide answer. In this given upto 100+ questions and shows answer or explanation under of each question.
Here all the questions and answers, most asked in different competitive exams and shows answers accordingly.
Q41. Can we use include (“abc.php”) two times in a php page “makeit.php”?
Answer:
yes
Q42.For printing out strings, there are echo, print and printf. Explain the differences.?
Answer:
echo is the most primitive of them, and just outputs the contents following the construct to the screen. print is also a construct (so parentheses are optional when calling it), but it returns TRUE on successful output and FALSE if it was unable to print out the string.
However, you can pass multiple parameters to echo, like:
<?php echo ‘Welcome ‘, ‘to’, ‘ ‘, ‘fyicenter!’; ?>
and it will output the string “Welcome to fyicenter!” print does not take multiple parameters. It is also generally argued that echo is faster, but usually the speed advantage is negligible, and might not be there for future versions of PHP. printf is a function, not a construct, and allows such advantages as formatted output, but it’s the slowest way to print out data out of echo, print and printf.
However, you can pass multiple parameters to echo, like:
<?php echo ‘Welcome ‘, ‘to’, ‘ ‘, ‘fyicenter!’; ?>
and it will output the string “Welcome to fyicenter!” print does not take multiple parameters. It is also generally argued that echo is faster, but usually the speed advantage is negligible, and might not be there for future versions of PHP. printf is a function, not a construct, and allows such advantages as formatted output, but it’s the slowest way to print out data out of echo, print and printf.
Q43. I am writing an application in PHP that outputs a printable version of driving directions. It contains some long sentences, and I am a neat freak, and would like to make sure that no line exceeds 50 characters. How do I accomplish that with PHP?
Answer:
On large strings that need to be formatted according to some length specifications, use
wordwrap() or chunk_split().
Q44. What’s the output of the ucwords function in this example?
Answer:
$formatted = ucwords(“FYICENTER IS COLLECTION OF INTERVIEW QUESTIONS”);
print $formatted;
What will be printed is FYICENTER IS COLLECTION OF INTERVIEW QUESTIONS.
ucwords() makes every first letter of every word capital, but it does not lower-case anything else. To avoid this, and get a properly formatted string, it’s worth using strtolower() first.
print $formatted;
What will be printed is FYICENTER IS COLLECTION OF INTERVIEW QUESTIONS.
ucwords() makes every first letter of every word capital, but it does not lower-case anything else. To avoid this, and get a properly formatted string, it’s worth using strtolower() first.
Q45.What’s the difference between htmlentities() and htmlspecialchars()?
Answer:
htmlspecialchars only takes care of <, >, single quote ‘, double quote ” and ampersand.
htmlentities translates all occurrences of character sequences that have different meaning in HTML.
htmlentities translates all occurrences of character sequences that have different meaning in HTML.
Q46.How can we extract string “abc.com” from a string “mailto:info@abc.com?subject=Feedback” using regular expression of PHP?
Answer:
$text = “mailto:info@abc.com?subject=Feedback”; preg_match(‘|.*@([^?]*)|’, $text, $output); echo $output[1];Note that the second index of $output, $output[1], gives the match, not the first one, $output[0].
Q47. So if md5() generates the most secure hash, why would you ever use the less secure crc32() and sha1()?
Answer:
Crypto usage in PHP is simple, but that doesn’t mean it’s free. First off, depending on thedata that you’re encrypting, you might have reasons to store a 32-bit value in the database instead of the 160-bit value to save on space. Second, the more secure the crypto is, the longer is the computation time to deliver the hash value. A high volume site might be significantly slowed down, if frequent md5() generation is required.
Q48. How can we destroy the session, how can we unset the variable of a session?
Answer:
session_unregister() – Unregister a global variable from the current session
session_unset() – Free all session variables
session_unset() – Free all session variables
Q49. What are the different functions in sorting an array?
Answer:
Sorting functions in PHP:
asort()
arsort()
ksort()
krsort()
uksort()
sort()
natsort()
rsort()
asort()
arsort()
ksort()
krsort()
uksort()
sort()
natsort()
rsort()
Q50. How can we know the count/number of elements of an array?
Answer:
2 ways:
a) sizeof($array) – This function is an alias of count()
b) count($urarray) – This function returns the number of elements in an array.
Interestingly if you just pass a simple var instead of an array, count() will return 1.
a) sizeof($array) – This function is an alias of count()
b) count($urarray) – This function returns the number of elements in an array.
Interestingly if you just pass a simple var instead of an array, count() will return 1.
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