LEARNING PHP AND MYSQL (2015)
Operators
Arithmetic operators
Example |
Name |
Result |
-$a |
Negation |
Opposite of $a |
$a + $b |
Addition |
Sum of $a and $b |
$a - $b |
Subtraction |
Difference of $a and $b |
$a*$b |
Multiplication |
Product of $a and $b |
$a / $b |
Division |
Quotient of $a and $b |
$a % $b |
Modulus |
Remainder of $a and $b |
The division operator would return float value unless the two operands are integers.
Example
<? php
Echo (5 % 3).”\n”;
Echo (5 % -3).”\n”;
Echo (-5 %3).”\n”;
Echo (-5%-3).”\n”;
?>
Assignment operator
There are two types of assignment operators which are commonly used in PHP. These are represented as “=” and “=>”.
Example
<? php
$a= ($b = 4) + 5;
?>
Bitwise operator
It allows evaluation and manipulation of a specific bit.
Example |
Name |
Result |
$a & $b |
And |
Are set in both $a and $b |
$a | $b |
Or |
Are set in either $a or $b |
$a ^ $b |
Xor |
Not in both |
~ $a |
Not |
Are set in $a are not set |
$a≪ $b |
Shift left |
Shifts bits of $a $b to left |
$a≫$b |
Shift right |
Shift bits of $a $b to right |
Comparison operator
It allows the comparison to be done by the use.
Example |
Name |
Result |
$a==$b |
Equal |
True if $a=$b |
$a===$b |
identical |
True if $a=$b |
$a!=$b |
Not equal |
True if $a≠$b |
$a<>$b |
Not equal |
True if $a≠$b |
$a!==$b |
Not identical |
True if $a≠$b |
$a<$b |
Less than |
True if $a strictly less than $b |
$a>$b |
Greater than |
True if $a greater than $b |
Error control operator
It is represented by ‘@ ‘. Using this it will ignore any error that is been intended by the expression.
Example
<? php
$my_file =@file (‘non_existent_file’)
$value = @$cache [$key];
?>
Execution operator
Supports execution operator: back ticks (“). Use of back tick is identical to the shell_exec ().
Example
<? php
$output = “ls – al”;
echo “<pre> $output</pre>;
?>
Increment decrement operator
They are pre and post increment decrement operator in c style.
Example |
Name |
Effect |
++$a |
Pre-increment |
Increases by one |
$a++ |
Post-increment |
Returns ,then increases |
--$a |
Pre-decrement |
Decreases then returns |
$a-- |
Post-decrement |
Returns then decreases |
Logical operator
The use of two different variables is to get different precedence as result.
Example |
Name |
Result |
$a and $b |
And |
True if both are true |
$a or $b |
Or |
True if either is true |
$a xor $b |
Xor |
True if either is true |
!$a |
Not |
True if $a is not true |
$a&&$b |
And |
True if both are true |
$a || $b |
Or |
True if either is true |