Slide môn học PHP session 2b PHP operators

PHP Operators
Session 5


Review - I
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An identifier is use to refer to the memory location
with the help of any variable
A data type describes the type of data a variable will
store. The different data types are:
 Integer numbers
 Floating numbers
 Strings
 Boolean
PHP / Session 5 / Slide 2 of 27


Review - II
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Numeric data or text enclosed in the quotes is considered to
be a string data type
Variable:
 Name assigned to a memory location where the data is
stored
 Enables to retrieve data from the memory location

 Dollar sign ‘$’ is placed before a variable name
 Variable created without any value assigned to it then
that variable takes its value as NULL
 Equal to sign ‘=’ is used to assign a value to the varaible
PHP / Session 5 / Slide 3 of 27


Review - III
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Local variable:
 Declared and used inside a function
 Lifetime remains till the function terminates
Global variable:
 Uses its value throughout the page
 Declared outside the function
 Called in the program with the help of the keyword global
Static variable:
 Local variable made static with the help of the keyword
static
 Retains its value even after the function terminates
PHP / Session 5 / Slide 4 of 27


Review - IV
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Environment variable:
 System-defined variable
 Provides information about the transactions held
between the client and the server
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Deals with the action of request and response
those are held in between the server and the client

PHP / Session 5 / Slide 5 of 27


Objectives
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Use Arithmetic operators
Use Logical operators
Use Relational operators
Use Bitwise operators
Use Assignment operators
Use String operators
Use Increment and Decrement Operators
PHP / Session 5 / Slide 6 of 27

Operators
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Operators are pre-defined symbols that allow
to perform specific actions
An expression contains operators and operands
The operators are assigned precedence values
This precedence value indicates the order in
which the operators are evaluated in an
expression
PHP / Session 5 / Slide 7 of 27


Arithmetic Operators - I
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Arithmetic Operators are used to perform operations
on numbers
We use the BODMAS rule to solve precedence
between the arithmetic operators.

Brackets are used to force precedence of operators

PHP / Session 5 / Slide 8 of 27


Arithmetic Operators - II
Following table lists the different arithmetic operators in PHP:

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Operator

Name

Description

+

Addition

Adds the operands

-

Subtraction

Subtracts the second operand from the first
operand

*

Multiplication Multiplies operands with each other

/

Division

Divides the first operand by the second operand

%

Modulus

Returns the remainder when the first operand is
divided by the second operand
PHP / Session 5 / Slide 9 of 27


Relational Operators - I
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Following table lists the different relational operators
in PHP
Operator

Name

Description

==

Equal to

Returns true if both the operands are equal

!=

Not equal to

Returns true if the first operand is not
equal to the second operand

<

Less than

Returns true if the first operand is less
than the second operand

PHP / Session 5 / Slide 10 of 27


Relational Operators - II
Operator

Name

Description

<=

Less than or equal to

Returns true if the first operand is
less than or equal to the second
operand

>

Greater than

Returns true if the first operand is
greater than the second operand

>=

Greater than or equal to

Returns true if the first operand is
greater than or equal to the second
operand

PHP / Session 5 / Slide 11 of 27


String Operators
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String operators operate on character data

Following table lists the different string operators in PHP

Operator

Name

Description

.

Concatenation

Returns a concatenated string

.=

Concatenating assignment Appends the argument on the right
side to the variable

PHP / Session 5 / Slide 12 of 27


Logical Operators
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Logical operators enable us to combine two
or more test expression in a condition
Evaluate expressions and return a Boolean

value

PHP / Session 5 / Slide 13 of 27


Logical Operators - I
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PHP provides us with the following logical
operators:
Operator

General Form

Description

&&

Expression1&& Expression2 Returns true only if both the
expressions are true

||

Expression1 || Expression2

Returns true if any one of
the expression is true

!

!Expression

Returns true only if the condition
is not true
PHP / Session 5 / Slide 14 of 27


Logical Operators - II
Operator

General Form

Description

AND

Expression1 AND Expression2

Returns true only if all the
expressions are true

OR

Expression1 OR Expression2

Returns true if any one of the
expression is true

XOR

Expression1 XOR Expression2

Returns false if both Expression1
and Expression2 are true or if both
Expression1 and Expression2 are
false and true otherwise.

PHP / Session 5 / Slide 15 of 27


Bitwise Operators - I
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Operate on the bits of an operand
Work on small-scale binary representation of
data

PHP / Session 5 / Slide 16 of 27


Bitwise Operators - II
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Following table lists the different bitwise operators in PHP:

Operator

Name

General Form

Description

&

AND

Operand1
Operand2

& Sets to 1 if both the bits of both the
operands are 1 and 0 otherwise

|

OR

Operand1 | Operand2

Sets to 1 if either of the bits of the
operands are 1 and 0 otherwise

PHP / Session 5 / Slide 17 of 27


Bitwise Operators - III
Operator

Name

General Form

^

EXCLUSIVE-OR Operand1
Operand2

~

COMPLEMENT

~ Operand

Description

^ Compares two bits and
sets the bit to 1 if the bits
are different and 0
otherwise
Compares and sets the bits
that are not set and 0
otherwise

PHP / Session 5 / Slide 18 of 27


Bitwise Operators - IV
Operator

Name

General Form

Description

<<

SHIFT
LEFT

Operand1 << Operand2

Shifts the bits of
Operand1,
Operand2
times to the left

>>

SHIFT
RIGHT

Operand1 >> Operand2

Shifts the bits of
Operand1,
Operand2
times to the right

PHP / Session 5 / Slide 19 of 27


Assignment Operator
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Enables us to set the operand on the left
side to the value of the expression on the
right side
‘=’ sign is the assignment operator
Different from the equal to ‘= ‘sign used as
the relational operator

PHP / Session 5 / Slide 20 of 27


Increment and Decrement
Operators - I
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Increment operators increase the value of the
operand by one
Decrement operators decrease the value of the

operand by one
These operators function more effectively
within loops such as for, do while, and while

PHP / Session 5 / Slide 21 of 27


Increment and Decrement
Operators - II
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Following table lists the different increment and decrement operators in
PHP:

Operand

Operator Name

Description

++$a

Pre-increment

Increments the operand value by one and
then returns this new value to the variable

$a++

Post-increment

Returns the value to the variable and then
increments the operand by one

PHP / Session 5 / Slide 22 of 27


Increment and Decrement
Operators - III
Operand Operator Name Description
--$a

Pre- decrement

Decrements the operand by one and then
returns this new value to the variable

$a--

Post decrement

Returns the value to the variable and then
decrements the operand by one

PHP / Session 5 / Slide 23 of 27


Precedence of Operators
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Following table lists illustrates the precedence of operators in PHP

Precedence
Highest Precedence

Operators
*, /, %
+, - , .
<, <=, >, >=
&&
||
AND
XOR

Lowest Precedence

OR

PHP / Session 5 / Slide 24 of 27


Summary - I
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An Operator is any symbol that performs an
operation on an operand. An operator enables us to
work on variables, strings, and numbers.

Operators enable to control the program flow
The types of operators are:
 Assignment Operators
 Arithmetic operators
 String Operators
 Logical Operators
 Incremental and
 Relational Operators
Decremental Operators
 Bitwise Operators

PHP / Session 5 / Slide 25 of 27