Operators in php

Php Operators :

There are many types of operators in php.

1. Arithmetic Operators
2. Comparison Operators
3. Assignment Operators
4. Increment/Decrement Operators
5. Logical Operators
6. String operators
7. Error Control Operators
8. Array Operators
9. Bitwise Operators
10. Type Operators
11. Execution Operators
12. Error Control Operators
    

    ---

1 Arithmetic Operators

+ (addition)
- ( subtraction) This operation work as a subtraction as well as negation
$a - $b ( this is the example of subtraction)
-$a ( this is the example of negation that means opposite of  $a )
* (multiplication)
% ( modulus
/ ( division)
** ( exponentiation )  ( This will work in PHP 5.6 version or later)

 Example of arithmetic operators :

<?php
$var1 = 100;
$var2 = 200;
$sum = $var1 + $var2;
$subtraction = $var2 - $var1;
$multiplication = $var1 * $var2;
$division = $var2/$var1;
$modulus = $var2%$var1;

echo "Sum  = $sum<br>";
echo "Subtraction  = $subtraction<br>";
echo "Multiplication  = $multiplication<br>";
echo "Division  = $division<br>";
echo "modulus = $modulus<br>";

?>
Output :
Sum = 300
Subtraction = 100
Multiplication = 20000
Division = 2
modulus = 0

---

2 Comparison Operators

==  ( Equal )
=== ( Identical )
!= (Not Equal )
!== ( Not Identical )
<> ( Not Equal )
>= ( Greater than or equal to )
<= ( Less than or equal to )
>  ( Greater than )
<  ( Less than )

Simple example of the above mentioned operators.

<?php
$var1 = 100;
$var2 = 100.00;
$var3 = 100.00;
$var4 = 50;
if($var1==$var2){
echo "Equal comparison operator<br>";
}
/**
* This condition work if and only if
*  both operands are same in value as well as data type
*  In this case $var1 and $var2 are same in value but not in data type.
*  So this condition will not work.
*/
if($var1===$var2){
echo "Identical comparison operator<br>";
}
/**
* This condition will work because $var2 and $var3 are same in value as well as data type
*/
if($var2===$var3){
echo "Identical comparison operator<br>";
}
if($var1 > 50){
echo "Greater than operator<br>";
}
if($var1 < 50){
echo "Less than operator<br>";
}
if($var1 >= 100){
echo "Greater than or equal operator<br>";
}
if($var1 <= 100){
echo "Less than or equal operator<br>";
}
if($var1 != $var4){
echo "Not equal operator<br>";
}
if($var1 <> $var4){
echo "Not equal operator<br>";
}
if($var1 !== $var2){
echo "Not identical operator<br>";
}
?>

Output :
Equal comparison operator
Identical comparison operator
Greater than operator
Greater than or equal operator
Less than or equal operator
Not equal operator
Not equal operator
Not identical operator

---

3 Assignment Operators

= ( This is assignment operator )

<?php
$a =100;
echo "Value of a = $a<br>";
$a+=100;    // $a = $a + 100;
echo "Value of a = $a<br>";
$a-=100;    //$a = $a-100
echo "Value of a = $a<br>";
$a*=100;     // $a = $a*100
echo "Value of a = $a<br>";
?>
Output :
Value of a = 100
Value of a = 200
Value of a = 100
Value of a = 10000

---

4 Increment/Decrement Operators

++ ( Increment Operator )
- -  ( Decrement Operator )

$a++   // $a++  and $a=$a+1 are same
$a--     // $a-- and $a=$a-1 are same

Understand with simple example.

1 )
<?php
$a = 100;
echo "Value of a = $a<br>";
/**
* Now you can increase the value of $a by 1
* using $a++( $a++ means $a=$a+1)
*/
$a++;
echo "After increment the value of a = $a<br>";
/**
* Now you can decrease the value of $a by 1
* using $a-- ( $a-- means $a=$a-1
*/
$a--;
echo "After decrement the value of a = $a<br>";
?>

Output :
Value of a = 100
After increment the value of a = 101
After decrement the value of a = 100

---

5 Logical Operators

There are three logical operators:
1) &&  ( And operator works on two operands  like $operand1 && $operand2)
2) ||  ( Or operator works on two operands like  $operand1 || $operand2)
3) !  ( Not operator  works on one operands like !$operand1)

Lets take a simple example to understand these all three operators.
You can copy past to check the blow code as well.

<?php

/**
 * 
 * In this block we will try to understand && logical operator
 */
$operand1=true;
$operand2=true;
if($operand1 && $operand2){  // If both are true then its work
    echo "Condition is true<br>";
}

$operand1=false;
$operand2=true;

if($operand1 && $operand2){  // If both are true then its work
    echo "If condition is true because of  both operands are true<br>";
}else{ //  If any of the operands or both operands are false then this block will work
    echo "Else block will execute because of any of the operands or both operands are false<br>";
}

/**
 * Output of the above block is below:
 * Condition is true
 * Else block will execute because of any of the operands or both operands are false
 */

/**
 * In this block we will try to understand ||  logical operator
 */

$operand1=false;
$operand2=true;

if($operand1 ||  $operand2){  // If any one operand is true then this block will work
    echo "Condition is true<br>";
}

$operand1=false;
$operand2=false;

if($operand1 || $operand2){  // If any one operand is true then this block will work
    echo 'If any one operand is true then this block will work<br>';
}else{ //  If  both operands are false then this block will work
    echo "Else block will execute because of both operands are false<br>";
}

/**
 * Output of the above block is below:
 * Condition is true
 * Else block will execute because of both operands are false
 */


/**
 * Lets take a example to understand ! (not) operator 
 */

$operand1=false;
if(!$operand1){   //  This means if not true then this block will work
    echo " This means if not true then this block will work<br>";
}

$operand1 =10;
if($operand1==10){
    echo "Operand1 value is 10<br>";
}
$operand1 =11;
if($operand1!=10){
    echo "Operand1 value is not 10<br>";
}

/**
 * Output of the above block is below:
 * This means if not true then this block will work
 * Operand1 value is 10Operand1 value is not 10
 */