21⟩ How to get number of characters in a String?
You can use the "strlen()" function to get the number of characters in a string. Here is a PHP script example of strlen():
<?php
print(strlen('It's Friday!'));
?>
This script will print:
12
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“PHP Developer Frequently Asked Questions by expert members with experience in PHP Developer. These questions and answers will help you strengthen your technical skills, prepare for the new job test and quickly revise the concepts”
57 PHP Developer Questions And Answers
22⟩ How you find a substring from a given string in PHP?
To find a substring in a given string, you can use the strpos() function. If you call strpos($haystack, $needle), it will try to find the position of the first occurrence of the $needle string in the $haystack string. If found, it will return a non-negative integer represents the position of $needle. Othewise, it will return a Boolean false. Here is a PHP script example of strpos():
<?php
$haystack1 = "2349534134345globalguideline16504381640386488129";
$haystack2 = "globalguideline234953413434516504381640386488129";
$haystack3 = "guideline234953413434516504381640386488129ggl";
$pos1 = strpos($haystack1, "globalguideline");
$pos2 = strpos($haystack2, "globalguideline");
$pos3 = strpos($haystack3, "globalguideline");
print("pos1 = ($pos1); type is " . gettype($pos1) . " ");
print("pos2 = ($pos2); type is " . gettype($pos2) . " ");
print("pos3 = ($pos3); type is " . gettype($pos3) . " ");
?>
This script will print:
pos1 = (13); type is integer
pos2 = (0); type is integer
pos3 = (); type is boolean
"pos3" shows strpos() can return a Boolean value
23⟩ Which is the best way to test the strpos() Return Value in PHP?
Because strpos() could two types of values, Integer and Boolean, you need to be careful about testing the return value. The best way is to use the "Identical(===)" operator. Do not use the "Equal(==)" operator, because it does not differentiate "0" and "false". Check out this PHP script on how to use strpos():
<?php
$haystack = "needle234953413434516504381640386488129";
$pos = strpos($haystack, "needle");
if ($pos==false) {
print("Not found based (==) test ");
} else {
print("Found based (==) test ");
}
if ($pos===false) {
print("Not found based (===) test ");
} else {
print("Found based (===) test ");
}
?>
This script will print:
Not found based (==) test
Found based (===) test
Of course, (===) test is correct.
24⟩ How you take a substring from a given string in PHP?
If you know the position of a substring in a given string, you can take the substring out by the substr() function. Here is a PHP script on how to use substr():
<?php
$string = "beginning";
print("Position counted from left: ".substr($string,0,5)." ");
print("Position counted form right: ".substr($string,-7,3)." ");
?>
This script will print:
Position counted from left: begin
Position counted form right: gin
substr() can take negative starting position counted from the end of the string.
25⟩ What does special set of tags do in PHP?
What does a special set of tags <?= and ?> do in PHP?
The output is displayed directly to the browser.
26⟩ How to repair MySQL table?
The syntex for repairing a mysql table is:
REPAIR TABLE tablename
REPAIR TABLE tablename QUICK
REPAIR TABLE tablename EXTENDED
This command will repair the table specified.
If QUICK is given, MySQL will do a repair of only the index tree.
If EXTENDED is given, it will create index row by row.
27⟩ Described persistent cookie in PHP?
A persistent cookie is a cookie which is stored in a cookie file permanently on the browser's computer. By default, cookies are created as temporary cookies which stored only in the browser's memory. When the browser is closed, temporary cookies will be erased. You should decide when to use temporary cookies and when to use persistent cookies based on their differences:
► Temporary cookies can not be used for tracking long-term information.
► Persistent cookies can be used for tracking long-term information.
► Temporary cookies are safer because no programs other than the browser can access them.
► Persistent cookies are less secure because users can open cookie files see the cookie values.
28⟩ How to know the number of days between two given dates using PHP?
Simple arithmetic:
$date1 = date('Y-m-d');
$date2 = '2006-07-01';
$days = (strtotime() - strtotime()) / (60 * 60 * 24);
echo "Number of days since '2006-07-01': $days";
29⟩ Where PHP configuration settings stored?
PHP stores configuration settings in a file called php.ini in PHP home directory. You can open it with any text editor to your settings.
30⟩ How to replace substring in a given string in PHP?
If you know the position of a substring in a given string, you can replace that substring by another string by using the substr_replace() function. Here is a PHP script on how to use substr_replace():
<?php
$string = "Warning: System will shutdown in NN minutes!";
$pos = strpos($string, "NN");
print(substr_replace($string, "15", $pos, 2)." ");
sleep(10*60);
print(substr_replace($string, "5", $pos, 2)." ");
?>
This script will print:
Warning: System will shutdown in 15 minutes!
(10 minutes later)
Warning: System will shutdown in 5 minutes!
Like substr(), substr_replace() can take negative starting position counted from the end of the string.
31⟩ Write the FORM Tag correctly for uploading files?
When users clicks the submit button, files specified in the <INPUT TYPE=FILE...> will be transferred from the browser to the Web server. This transferring (uploading) process is controlled by a properly written <FORM...> tag as:
<FORM ACTION=receiving.php METHOD=post ENCTYPE=multipart/form-data>
Note that you must specify METHOD as "post" and ENCTYPE as "multipart/form-data" in order for the uploading process to work. The following PHP code, called logo_upload.php, shows you a complete FORM tag for file uploading:
<?php
print("<html><form action=processing_uploaded_files.php"
." method=post enctype=multipart/form-data>n");
print("Please submit an image file a Web site logo for"
." rendc.org:
n");
print("<input type=file name=globalguideline_logo>
n");
print("<input type=submit>n");
print("</form></html>n");
?>
32⟩ Define constant in PHP?
Via define() directive, like define ("MYCONSTANT", 100);
33⟩ Can you please explain the difference between require and include, include_once?
require_once() and include_once() are both the functions to include and evaluate the specified file only once. If the specified file is included previous to the present call occurrence, it will not be done again.
But require() and include() will do it as many times they are asked to do.
The include_once() statement includes and evaluates the specified file during the execution of the script. This is a behavior similar to the include() statement, with the only difference being that if the code from a file has already been included, it will not be included again. The major difference between include() and require() is that in failure include() produces a warning message whereas require() produces a fatal errors.
34⟩ How to get uploaded file information in the Receiving Script?
Once the Web server received the uploaded file, it will call the PHP script specified in the form action attribute to process them. This receiving PHP script can get the uploaded file information through the predefined array called $_FILES. Uploaded file information is organized in $_FILES as a two-dimensional array as:
* $_FILES[$fieldName]['name'] - The Original file name on the browser system.
* $_FILES[$fieldName]['type'] - The file type determined by the browser.
* $_FILES[$fieldName]['size'] - The Number of bytes of the file content.
* $_FILES[$fieldName]['tmp_name'] - The temporary filename of the file in which the uploaded file was stored on the server.
* $_FILES[$fieldName]['error'] - The error code associated with this file upload.
The $fieldName is the name used in the <INPUT TYPE=FILE, NAME=fieldName>.
35⟩ Define urlencode and urldecode?
urlencode() returns the URL encoded version of the given string. URL coding converts special characters into % signs followed by two hex digits. For example: urlencode("10.00%") will return "10%2E00%25". URL encoded strings are safe to be used as part of URLs.
urldecode() returns the URL decoded version of the given string.
string urlencode(str) - Returns the URL encoded version of the input string. String values to be used in URL query string need to be URL encoded. In the URL encoded version:
Alphanumeric characters are maintained as is.
Space characters are converted to "+" characters.
Other non-alphanumeric characters are converted "%" followed by two hex digits representing the converted character.
string urldecode(str) - Returns the original string of the input URL encoded string.
For example:
$discount ="10.00%";
$url = "http://domain.com/submit.php?disc=".urlencode($discount);
echo $url;
You will get "http://domain.com/submit.php?disc=10%2E00%25".
36⟩ Can you please explain the difference between mysql_fetch_object and mysql_fetch_array?
MySQL fetch object will collect first single matching record where mysql_fetch_array will collect all matching records from the table in an array.
37⟩ How to execute a PHP script using command line?
Just run the PHP CLI (Command Line Interface) program and provide the PHP script file name as the command line argument. For example, "php myScript.php", assuming "php" is the command to invoke the CLI program.
Be aware that if your PHP script was written for the Web CGI interface, it may not execute properly in command line environment.
38⟩ Can I use print "$a dollars" or "{$a} dollars" to print out the amount of dollars in this example?
In this example it wouldn't matter, since the variable is all by itself, but if you were to print something like "{$a},000,000 mln dollars", then you definitely need to use the braces.
39⟩ I am trying to assign variable the value of 0123, but it keeps coming up with a different number, what is the problem?
PHP Interpreter treats numbers beginning with 0 as octal. Look at the similar PHP interview questions for more numeric problems.
40⟩ List the different tables present in MySQL?
Total 5 types of tables we can create:
1) MyISAM
2) Heap
3) Merge
4) INNO DB
5) ISAM
