Php basics

PHP Basics
Jamshid Hashimi
Trainer, Cresco Solution
http://www.jamshidhashimi.com
jamshid@netlinks.af
@jamshidhashimi
ajamshidhashimi
Afghanistan Workforce
Development Program

AGENDA
• About PHP & MySQL
• Advantage of using PHP for Web Development
• PHP Installation, PHP Syntax & PHP Variable
• PHP Strings
• PHP Operators
• Conditional Statements
– if (...else) Statement
– Switch Statements
• Exercise!

PHP: Introduction
• PHP is a programming language for building
dynamic, interactive Web sites. As a general
rule, PHP programs run on a Web server, and
serve Web pages to visitors on request. One of
the key features of PHP is that you can embed
PHP code within HTML Web pages, making it
very easy for you to create dynamic content
quickly.

PHP: Introduction
• PHP stands for PHP: Hypertext Preprocessor,
which gives you a good idea of its core
purpose: to process information and produce
hypertext (HTML) as a result.
• PHP is a server-side scripting language, which
means that PHP scripts, or programs, usually
run on a Web server. (A good example of a
client-side scripting language is JavaScript,
which commonly runs within a Web browser.)

PHP: The Process
• A visitor requests a Web page by clicking a link, or
typing the page’s URL into the browser’s address bar.
The visitor might also send data to the Web server at
the same time, either using a form embedded in a Web
page, or via AJAX (Asynchronous JavaScript And XML).
• The Web server recognizes that the requested URL is a
PHP script, and instructs the PHP engine to process and
run the script.
• The script runs, and when it’s finished it usually sends
an HTML page to the Web browser, which the visitor
then sees on their screen.

PHP
• PHP: Hypertext Preprocessor
• Appeared in: 1995; 18 years ago
• Designed by: Rasmus Lerdorf
• Developer: The PHP Group
• Stable release: 5.4.15 (May 9, 2013; 25 days ago)
• Typing discipline: Dynamic, weak
• Influenced by: Perl, C, C++, Java, Tcl
• Implementation language: C
• OS: Cross-platform
• License: PHP License
• Usual filename extensions .php, .phtml, .php4 .php3,
.php5, .phps

Why PHP?
• Easy to learn
• Familiarity with syntax
• Free of cost
• Efficiency in performance
• A helpful PHP community
• Cross Platform

MySQL
• MySQL is the most popular database system used with PHP.
• MySQL is a database system used on the web
• MySQL is a database system that runs on a server
• MySQL is ideal for both small and large applications
• MySQL is very fast, reliable, and easy to use
• MySQL supports standard SQL
• MySQL compiles on a number of platforms
• MySQL is free to download and use
• MySQL is developed, distributed, and supported by Oracle
Corporation
• MySQL is named after co-founder Monty Widenius's daughter: My

PHP Editor + W(M)AMP Installation

PHP Syntax
• Basic PHP Syntax
<?php
// PHP code goes here
?>
<!DOCTYPE html>
<html>
<body>
<h1>My first PHP page</h1>
<?php
echo "Hello World!";
?>
</body>
</html>

PHP Variables
• Variables are a fundamental part of any
programming language. A variable is simply a
container that holds a certain value.
echo 2 + 2;
echo 5 + 6;
echo $x + $y;

PHP Variables
• A variable starts with the $ sign, followed by the
name of the variable
• A variable name must begin with a letter or the
underscore character
• A variable name can only contain alpha-numeric
characters and underscores (A-z, 0-9, and _ )
• A variable name should not contain spaces
• Variable names are case sensitive ($y and $Y are
two different variables)

Strings: Examples
Valid examples of strings:
$string1 = "This is a string in double
quotes";
$str = 'This is a somewhat longer, singly
quoted string';
$string2 = ""; // a string with zero
characters

Strings: Examples
Single quote strings vs. Double quote strings:
$variable = "name";
$text = "My $variable will print!";
echo $text;
> My name will print!
$text = 'My $variable will not print!';
echo $text;
> My $variable will not print!

Strings: Concatenation(.)
• String concatenation is the string
manipulation method when you join 2 or
more strings together.
$str1 = ”AWD Training";
$str2 = "-Cresco Solutions";
echo $str1.$str2;
> AWD Training-Cresco Solutions

Strings: strlen()
• Returns the length of the string
$str = "Kabul is the capital of
Afghanistan";
echo strlen($str);
> 35

Strings: explode()
• explode — Split a string by string
$str = "This is a somewhat longer, singly
quoted string";
$new_str = explode(" ",$str);
print_r($new_str);
>Array ( [0] => This [1] => is [2] => a [3]
=> somewhat [4] => longer, [5] => singly
[6] => quoted [7] => string )

Strings: strpos()
• strpos — Find the position of the first
occurrence of a substring in a string
Afghanistan";
$position = strpos($str,"capital");
echo $position;
> 13

Strings: strtoupper()
• strtoupper — Make a string uppercase
$str = "Kabul is the capital of Afghanistan";
echo strtoupper($str);
> KABUL IS THE CAPITAL OF AFGHANISTAN

Strings: strtolower()
• strtolower — Make a string lowercase
Afghanistan";
echo strtolower($str);
> kabul is the capital of afghanistan

Strings: ucfirst()
• ucfirst — Make a string's first character
uppercase
$str = "afghanistan";
echo ucfirst($str);
> Afghanistan

Strings: lcfirst()
• lcfirst — Make a string's first character
lowercase
$str = "Afghanistan";
echo lcfirst($str);
> afghanistan

Strings: trim()
• trim — Strip whitespace (or other characters)
from the beginning and end of a string
$str = ” Afghanistan is the heart of
Asia";
var_dump($str);
>string(36) “Afghanistan is the heart of
Asia"
$str = ” Afghanistan is the heart of
Asia";
var_dump(trim($str));
> string(32) "Afghanistan is the heart of
Asia”

Strings: str_replace()
• str_replace — Replace all occurrences of the
search string with the replacement string
$str = "Balkh is the capital of
Afghanistan";
echo str_replace("Balkh","Kabul",$str);
> Kabul is the capital of Afghanistan

Strings: substr()
• substr — Return part of a string
$str = "Afghanistan is the heart of Asia";
echo substr($str,12);
> is the heart of Asia
echo substr($str,12,12);
> is the heart
echo substr($str,-4);
> Asia

Operators
• In all programming languages, operators are
used to manipulate or perform operations on
variables and values.
– PHP Arithmetic Operators
– PHP Assignment Operators
– PHP Incrementing/Decrementing Operators
– PHP Comparison Operators
– PHP Logical Operators

Operators: Increment & Decrement

Conditional Statements
if (condition)
{
code to be executed if condition is true;
}
if (condition)
{
code to be executed if condition is
true;
}
else
{
code to be executed if condition is
false;
}

if (condition)
{
}
else if (condition)
{
}
else
{
code to be executed if condition is false;
}

switch (n)
{
case label1:
code to be executed if n=label1;
break;
case label2:
code to be executed if n=label2;
break;
default:
code to be executed if n is different from both label1
and label2;
}

Exercise!
• Write a program called CheckPassFail which
prints "PASS" if the int variable "mark" is more
than or equal to 50; or prints "FAIL"
otherwise.
• Write a program called CheckOddEven which
prints "Odd Number" if the int variable
“number” is odd, or “Even Number”
otherwise.

Exercise!
• Write a program which add, subtract, divide
and multiply two number and show the result
on the screen.
• Write a program to find the biggest positive
number among a,b,c,d numbers
• Write a program which returns the average of
given 3 number

Exercise!
• Write a program which categorize people
according to their work experience:
0: Fresh Graduate
1-3: Mid-Level
4-8: Senior Level
9-30: Superman
• Write a program which outputs the quarter
(Q1,Q2,Q3,Q4) of the year a given date is in.
– e.g. 17 June 2013 output must be: Q2 2013

Php basics

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