<?php
// define $total as 10
$total = 10;
// increment it
$total++;
// $total is now 11

?>

Thus, <?php $total++; ?> is functionally equivalent to <?php
$total = $total + 1; ?>.
There’s also a corresponding auto-decrement operator (––), which does exactly the opposite:

<?php
// define $total as 10
$total = 10;
// decrement it
$total--;
// $total is now 9

?>

These operators are frequently used in loops to update the value of the loop counter.

for today i will discuss about PHP Logical Operators.

To link together related conditions in a simple and elegant manner, we can use one of PHP’s four Logical Operators -logical AND, logical OR, logical XOR, and logical NOT-as illustrated in the following listing.

<?php
// define some variables
$username = 'daniel';
$password = 'dumas';
$saveCookie = 1;
$status = 1;

// logical AND
// returns true if all conditions are true
// returns true here
$result = (($username == 'daniel') && ($password == 'dumas'));

// logical OR
// returns true if any conditions is true
// returns false here
$result = (($status < 1) || ($saveCookie == 0)); 

// logical NOT
// returns true if the condition is false and vice-versa
// returns false
$result = !($saveCookie == 1); 

// logical XOR
// returns true if any of the two conditions are true
// returns false if both conditions are true
// returns false here

$result = (($status == 1) xor ($saveCookie == 1));

?>

As a Web Developer or Web Designer, it is important that website’s we develop are working on all major browsers, or on all(old or new) browsers if possible. but some browsers (specially the old one’s) has their own specific way of translating or handling css /style directions.

And also sometimes we need to show or hide some specific elements for some browsers or browser versions.

for situations like the above, stylesheet separation for specific browsers can help.  look at the codes below.

<?php
if(strstr($_SERVER['HTTP_USER_AGENT'], "MSIE 6")){
?>
<link rel="stylesheet" type="text/css" href="/css/ie6.css" />
<?php
} elseif(strstr($_SERVER['HTTP_USER_AGENT'], "MSIE 7")) {
?>
<link rel="stylesheet" type="text/css" href="/css/ie7.css" />
<?php
} elseif(strstr($_SERVER['HTTP_USER_AGENT'], "MSIE 8")) {
?>
<link rel="stylesheet" type="text/css" href="/css/ie8.css" />
<?php
} elseif(strstr($_SERVER['HTTP_USER_AGENT'], "Firefox")) {
?>
<link rel="stylesheet" type="text/css" href="/css/ff.css" />
<?php
} elseif(strstr($_SERVER['HTTP_USER_AGENT'], "Chrome")){
?>
<link rel="stylesheet" type="text/css" href="/css/chr.css" />
<?php
} elseif(strstr($_SERVER['HTTP_USER_AGENT'], "Safari")){
?>
<link rel="stylesheet" type="text/css" href="/css/saf.css" />
<?php
}
?>

what this codes do is detect the users browser then prints the specific stylesheet for that browser. you can put this code directly below your main CSS stylesheet, because the primary use of this code is to override the main CSS settings. so for example a div is showing differently in IE6 browser, you can just include the style direction of this div into the ie6.css, so when a user browse your website using IE6 browser, the main CSS setting for this div will be override by ie6.css.

the code above can also be used on a wordpress blog or wordpress based sites, you just need to add your wordpress site’s template url to the CSS path. please look at the code below.

<?php
if(strstr($_SERVER['HTTP_USER_AGENT'], "MSIE 6")){
?>
<link rel="stylesheet" type="text/css" href="<?php bloginfo('template_url'); ?>/css/ie6.css" />
<?php
} elseif(strstr($_SERVER['HTTP_USER_AGENT'], "MSIE 7")) {
?>
<link rel="stylesheet" type="text/css" href="<?php bloginfo('template_url'); ?>/css/ie7.css" />
<?php
} elseif(strstr($_SERVER['HTTP_USER_AGENT'], "MSIE 8")) {
?>
<link rel="stylesheet" type="text/css" href="<?php bloginfo('template_url'); ?>/css/ie8.css" />
<?php
} elseif(strstr($_SERVER['HTTP_USER_AGENT'], "Firefox")) {
?>
<link rel="stylesheet" type="text/css" href="<?php bloginfo('template_url'); ?>/css/ff.css" />
<?php
} elseif(strstr($_SERVER['HTTP_USER_AGENT'], "Chrome")){
?>
<link rel="stylesheet" type="text/css" href="<?php bloginfo('template_url'); ?>/css/chr.css" />
<?php
} elseif(strstr($_SERVER['HTTP_USER_AGENT'], "Safari")){
?>
<link rel="stylesheet" type="text/css" href="<?php bloginfo('template_url'); ?>/css/saf.css" />
<?php
}
?>

You can insert this code into your wordpress theme’s header file (header.php), directly below the main CSS declaration:

<link rel="stylesheet" href="<?php bloginfo('stylesheet_url'); ?>" type="text/css" media="screen" />

Enjoy! please share.

<?php
//define variables..
$str = '9';
$int = 9;

//Returns true since both variable contains the same value..
$res = ($str==$int);

//Returns false since the two variables are not of the same type..
$res = ($str===$int);
?>

I. Define the Variables

<?php
$num1 = 9;
$num2 = 9;
$num3 = 22;
?>

A. The Less Than Operator

<?php
//Returns true if variable in the left side is less than the right..
$res = ($num1 < $num3);
//returns true..
?>

B. The Greater Than Operator

<?php
//Returns true if the variable in left side is greater that the right..
$res = ($num3 > $num1);
//returns true..
?>

C. The Less Than or Equal-to Operator

<?php
//returns true if variable on left is less than or equal to right..
$res = ($num3 <= $num1);
//returns false
?>

D. The Greater Than or Equal-to Operator

<?php
//returns true if variable on left is greater than or equal to right..
$res = ($num3 >= $num2);
//returns true..
?>

E. The Equality Operator

<?php
//returns true if both variables are equal to each other
$res = ($num1 == $num2);
//returns true..
?>

F. The Not Equal-to Operator

<?php
//returns true if the variable on left is not equal to right
$res = ($num1 != $num2);
//returns false..
?>

G. The Inequality Operator

<?php
//returns true if the variable on left is not equal to right..
$res = ($num1 <> $num2);
//returns false..
?>

<?php
// intialize variables
$username = "daniel";
$domain = "danieldumas.com";

// the variable string $username and $domain can be combine using the concatenation operator
$email_address = $username . '@'. $domain;

//the variable $email_address now contains the value "daniel@danieldumas.com"

?>

You can also concatenate simultaneously. .

<?php

$name = "dan";

//add and assign values to the string $name..

$name .= "iel";

//the variable $name now contains "daniel"

?>

Using PHP Arithmetic Operator

//define variables
<?php

$num1 = 50;
$num2 = 30;

//Addition
$sum = $num1 + $num2;

//Subtraction
$difference = $num1 - $num2;

//Multiplication
$product = $num1*$num2;

//Division
$quotient = $num1 / $num2;

//Modulus
$remainder = $num1 % $num2;

?>

you may also use the shorthand using the PHP Assignment Operator and Arithmetic Operator together.

PHP Assignment Operator and Arithmetic Operator Together

//define variables

< ?php

$num1 = 50;
$num2 = 30;

//Addition
$num1 = $num1+ $num2;
//Shorthand for this is..
$num1+=$num2;

//Subtraction
$num1 = $num1 - $num2;
//Shorthand for this is..
$num1-=$num2;

//Multiplication
$num1 = $num1 * $num2;
//Shorthand for this is..
$num1 *=$num2;

//Division
$num1 = $num1 / $num2;
//Shorthand for this is..
$num1 /=$num2;

//Modulus
$num1= $num1 % $num2;
//Shorthand for this is..
$num1%=$num2;

?>

Below is a list of PHP Operators and its function

<?php

//define variables
$on = true;
$age = 20;
$name = "daniel";
$price = 99.99;

//Returns Boolean
echo gettype($on);

//Returns String
echo gettype($name);

//Returns Integer
echo gettype($age);

//Returns Double
echo gettype($price);

?>

You can also use other PHP functions to determine the datatypes of a variable

Example 1: Processing forms in the same php file

Copy and Paste the code below to your text editor and save it as form.php, then run it on your localhost

<html>
<head>
<title>Saving Form Input in PHP Variables</title>
</head>
<body>

<form method="post">
Enter message : <input type="text" name="msg">
<input type="submit" value="Print Msg">

<?php
// stores the form data into a php variable
$msg = $_POST['msg'];
//Prints the data retrieve from the form
echo "You said: <b>$msg</b>";
?>

</body>
</html>

Example 2: Processing Form using external php file

Copy and Save the code below to your text editor and save it as form2.php

<html>
<head>
<title>Saving Form Input in PHP Variables</title>
</head>
<body>

<form action="msghandler.php" method="post">
Enter message : <input type="text" name="msg">
<input type="submit" value="Print Msg">

</body>
</html>

Copy and Save the code below to your text editor and save it as msghandler.php in the same folder where form2.php is located, this is the php script that will process the form2.php above

<?php
// stores the form data into a php variable
$msg = $_POST['msg'];
//Prints the data retrieve from the form
echo "You said: <b>$msg</b>";
?>

You Should Get this output in your browser. .

Before clicking the print button

After Clicking the print button