PHPArūnas Liuiza

PHP 101

What is PHP?

Widely popular dynamic interpreted opensource programming language, aimed for web development

Syntax is simmilar to C, Perl, Java

PHP code snippets can be inserted to a HTML document

PHP Syntax

Inserting to HTML

Long tags <?php ... ?> <script language=“php”> ... </script>

Short tags <? ... ?> ir <?= ... ?> <% ... %> ir <%= ... ?>

Not recommended due to compatability reasons

Output

Main function to output data: echo

echo “Hello”; echo 12345;

ĮTERPIMAS Į HTML. PAVYZDYS

Instruction separation

Semicolon (;) is used to separate instructions from one another

<?php echo “foo”; echo “bar”;?>

Comments

PHP has three types of comments

Single line (till the end of line or ?>) : // comment # comment

Multi-line /* comment

carries to another line and another… */

Variables Symbolic name, that

can have a value assigned to it

Starts with dollar ($) sign $first

First symbol has to be a letter or an underscore (_) $start $_with_underscore

Can also contain numbers $p123_44dlsdm_ $_1234ps

Variable names are Case Sensitive $Pirmas != $pirmas $DuKartai != $dukartai

Variables. Examples

$foo = 15;echo ‘foo is ‘.$foo;

$foo = “Peter”;echo ‘foo is ‘.$foo;

$foo = “Peter”;$foo = “John”;echo ‘foo is ‘.$foo;

foo is 15

foo is Peter

foo is John

Code Result

Main PHP data types

Boolean Logical true/false

Integer 1, 2, 3, 4…

Float 3.1415, 0.21513

String ‘Text’

Array

Object

Resource

NULL No value

BOOLEAN Logical true or false value

$a = true; $a = FaLsE;

Possible FALSE values: FALSE 0 0.0 ‘’ ir ‘0’ Empty array Object without members NULL

Anything else - TRUE

Type casting

PHP does not require strict definition of variable data type – type is converted according to context

Operators

PHP operators are divided to: Arithmetical Value assigning Comparison Logical

Arithmetical

+ Sum $a = 2 + 2

- Subtract $a = 4 – 2

* Multiply $a = 2 * 2

/ Divide $a = 4 / 2

% Division module $a = 5 % 2 (=1)

++

Add 1 ++$a

-- Subtract 1 --$a

. Connect two strings

$a = “raga” . “nosis”

Value assigning

= $x = $y

+=

$x += $y $x = $x + $y

-= $x -= $y $x = $x - $y

*= $x *= $y $x = $x * $y

/= $x /= $y $x = $x / $y

.= $x .= $y $x = $x . $y

%=

$x %= $y $x = $x % $y

Comparison

==

Equal 5==8 false

!= Not equal 5!=8 true

<>

Not equal 5<>8 true

> More 5>8 false

< Less 5<8 true

>=

More or equal 5>=8 false

<=

Less or equal 5<=5 true

Logical

&& AND

|| OR

! NOT

Exercise

Task no 1

1. Multiply N by 32. Add 15 to the result3. Find module of

division by 4 of the result

4. Add 2 to the result5. Raise the result to

the second power (Res2)

6. Subtract 1.5 from the result

7. Divide result by 3

Write a program that executes the operations one by one, outputing the result after each operation