Web Hosting Web Hosting, website hosting, web site hosting , web page hosting Apache, PHP, MySQL, PERL, servlets Java, JSP  Web Hosting Web Hosting website hosting, web site hosting, web page hosting Apache, PHP, MySQL, PERL, servlets Java, JSP,Python Web Hosting Web Hosting website hosting, web site hosting, web page hosting Apache, PHP, MySQL, PERL, servlets Java, JSP,Python Web Hosting Web Hosting website hosting, web site hosting, web page hosting Apache, PHP, MySQL, PERL, servlets Java, JSP,Python Web Hosting Web Hosting website hosting, web site hosting, web page hosting, Apache, PHP, MySQL, PERL, servlets Java, JSP,Python
Web Hosting Web Hosting, website hosting, web site hosting, web page hosting, Apache, PHP, MySQL, PERL, servlets Java, JSP, Python Web Hosting Web Hosting, website hosting, web site hosting, web page hosting, Apache, PHP, MySQL, PERL, servlets Java, Python,JSP
Web Hosting Web Hosting Sign-Up Web Hosting Fund Raising, Fundraising, web hosting, website hosting, web site hosting  Web Hosting Resellers web hosting, website hosting, web site hosting Web Hosting EZ Site Control Panel for web hosting,website hosting, web site hosting
Web Hosting Web Hosting, website hosting, web site hosting , web page hosting Apache, PHP, MySQL, PERL, servlets Java, Python,JSP,  Fundraising
Web Hosting Fund Raising, Fundraising, web hosting, website hosting, web site hosting
WWW.

Call Us Toll-Free
(877) 256-0328

Outside USA
1 - (201) 505-0430

Web Hosting Welcome Web Hosting Web Hosting Plans Overview , Fund Raising, Fundraising, web hosting, website hosting, web site hosting Web Hosting Fund Raising, Fundraising, web hosting Web Hosting Resellers, web Hosting Web Hosting Web Design, web Hosting Web Hosting Extra Services,  web Hosting Web Hosting Traffic Booster, web hosting Web Hosting Traffic Booster, web hosting Web Hosting Technical Support,  web Hosting Web Hosting webmaster tips,  web Hosting Web Hosting 30 Day Money Back, web hosting Web Hosting Legal Notices for Web Hosting Web Hosting Glossary Computer Terms for web Hosting Web Hosting Contact Information - web hosting

Site Map
Web Hosting Web Hosting, website hosting, web site hosting , web page hosting Apache, PHP, MySQL, PERL, servlets Java, Python, JSP Web Hosting Web Hosting Web Hosting Web Hosting Web Hosting Comparison Operators

Comparison Operators

Comparison operators, as their name implies, allow you to compare two values. You may also be interested in viewing the type comparison tables, as they show examples of various type related comparisons.

Table 15-4. Comparison Operators

ExampleNameResult
$a == $bEqualTRUE if $a is equal to $b.
$a === $bIdentical TRUE if $a is equal to $b, and they are of the same type. (introduced in PHP 4)
$a != $bNot equalTRUE if $a is not equal to $b.
$a <> $bNot equalTRUE if $a is not equal to $b.
$a !== $bNot identical TRUE if $a is not equal to $b, or they are not of the same type. (introduced in PHP 4)
$a < $bLess thanTRUE if $a is strictly less than $b.
$a > $bGreater thanTRUE if $a is strictly greater than $b.
$a <= $bLess than or equal to TRUE if $a is less than or equal to $b.
$a >= $bGreater than or equal to TRUE if $a is greater than or equal to $b.

If you compare an integer with a string, the string is converted to a number. If you compare two numerical strings, they are compared as integers. These rules also apply to the switch statement.

<?php
var_dump
(0 == "a"); // 0 == 0 -> true
var_dump("1" == "01"); // 1 == 1 -> true

switch ("a") {
case
0:
    echo
"0";
    break;
case
"a": // never reached because "a" is already matched with 0
    
echo "a";
    break;
}
?>

For various types, comparison is done according to the following table (in order).

Table 15-5. Comparison with Various Types

Type of Operand 1Type of Operand 2Result
null or stringstringConvert NULL to "", numerical or lexical comparison
bool or nullanythingConvert to bool, FALSE < TRUE
objectobjectBuilt-in classes can define its own comparison, different classes are uncomparable, same class - compare properties the same way as arrays (PHP 4), PHP 5 has its own explanation
string, resource or numberstring, resource or numberTranslate strings and resources to numbers, usual math
arrayarrayArray with fewer members is smaller, if key from operand 1 is not found in operand 2 then arrays are uncomparable, otherwise - compare value by value (see following example)
arrayanythingarray is always greater
objectanythingobject is always greater

Example 15-2. Transcription of standard array comparison

<?php
// Arrays are compared like this with standard comparison operators
function standard_array_compare($op1, $op2)
{
    if (
count($op1) < count($op2)) {
        return -
1; // $op1 < $op2
    
} elseif (count($op1) > count($op2)) {
        return
1; // $op1 > $op2
    
}
    foreach (
$op1 as $key => $val) {
        if (!
array_key_exists($key, $op2)) {
            return
null; // uncomparable
        
} elseif ($val < $op2[$key]) {
            return -
1;
        } elseif (
$val > $op2[$key]) {
            return
1;
        }
    }
    return
0; // $op1 == $op2
}
?>

See also strcasecmp(), strcmp(), Array operators, and the manual section on Types.

Ternary Operator

Another conditional operator is the "?:" (or ternary) operator.

Example 15-3. Assigning a default value

<?php
// Example usage for: Ternary Operator
$action = (empty($_POST['action'])) ? 'default' : $_POST['action'];

// The above is identical to this if/else statement
if (empty($_POST['action'])) {
    
$action = 'default';
} else {
    
$action = $_POST['action'];
}

?>
The expression (expr1) ? (expr2) : (expr3) evaluates to expr2 if expr1 evaluates to TRUE, and expr3 if expr1 evaluates to FALSE.

Note: Please note that the ternary operator is a statement, and that it doesn't evaluate to a variable, but to the result of a statement. This is important to know if you want to return a variable by reference. The statement return $var == 42 ? $a : $b; in a return-by-reference function will therefore not work and a warning is issued in later PHP versions.

Note: Is is recommended that you avoid "stacking" ternary expressions. PHP's behaviour when using more than one ternary operator within a single statement is non-obvious:

Example 15-4. Non-obvious Ternary Behaviour

<?php
// on first glance, the following appears to output 'true'
echo (true?'true':false?'t':'f');

// however, the actual output of the above is 't'
// this is because ternary expressions are evaluated from left to right

// the following is a more obvious version of the same code as above
echo ((true ? 'true' : 'false') ? 't' : 'f');

// here, you can see that the first expression is evaluated to 'true', which
// in turn evaluates to (bool)true, thus returning the true branch of the
// second ternary expression.
?>

 
 
 

Add to My Yahoo!

XML icon

Add to Google

 

 

 

 

 

 

 

 

 

 

 

http://alden-servlet-Hosting.com
JSP at alden-servlet-Hosting.com
Servlets at alden-servlet-Hosting.com
Servlet at alden-servlet-Hosting.com
Tomcat at alden-servlet-Hosting.com
MySQL at alden-servlet-Hosting.com
Java at alden-servlet-Hosting.com
sFTP at alden-servlet-Hosting.com
http://alden-tomcat-Hosting.com
JSP at alden-tomcat-Hosting.com
Servlets at alden-tomcat-Hosting.com
Servlet at alden-tomcat-Hosting.com
Tomcat at alden-tomcat-Hosting.com
MySQL at alden-tomcat-Hosting.com
Java at alden-tomcat-Hosting.com
sFTP at alden-tomcat-Hosting.com
http://alden-sftp-Hosting.com
JSP at alden-sftp-Hosting.com
Servlets at alden-sftp-Hosting.com
Servlet at alden-sftp-Hosting.com
Tomcat at alden-sftp-Hosting.com
MySQL at alden-sftp-Hosting.com
Java at alden-sftp-Hosting.com
sFTP at alden-sftp-Hosting.com
http://alden-jsp-Hosting.com
JSP at alden-jsp-Hosting.com
Servlets at alden-jsp-Hosting.com
Servlet at alden-jsp-Hosting.com
Tomcat at alden-jsp-Hosting.com
MySQL at alden-jsp-Hosting.com
Java at alden-jsp-Hosting.com
sFTP at alden-jsp-Hosting.com
http://alden-java-Hosting.com
JSp at alden-java-Hosting.com
Servlets at alden-java-Hosting.com
Servlet at alden-java-Hosting.com
Tomcat at alden-java-Hosting.com
MySQL at alden-java-Hosting.com
Java at alden-java-Hosting.com
sFTP at alden-java-Hosting.com
JSP Servlets Tomcat mysql Java JSP Servlets Tomcat mysql Java JSP Servlets Tomcat mysql Java JSP Servlets Tomcat mysql Java JSP at JSP.aldenWEBhosting.com Servlets at servlets.aldenWEBhosting.com Tomcat at Tomcat.aldenWEBhosting.com mysql at mysql.aldenWEBhosting.com Java at Java.aldenWEBhosting.com Web Hosts Portal Web Links Web Links Web Hosting JSP Solutions Web Links JSP Solutions Web Hosting Servlets Solutions Web Links Servlets Solutions Web Hosting Web Links Web Links . .
.
.
. .
. . . . . . jsp hosting servlets hosting web hosting web sites designed cheap web hosting web site hosting myspace web hosting