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PHP: Subhash's Jump Start Guide

Before We Start ...

According to Rasmus Lerdorf (creator of PHP), PHP is "a server-side, HTML-embedded, cross-platform scripting language". To my knowledge, PHP when expanded becomes "PHP Hypertext Pre-processor". You can get the latest distribution of PHP from PHP.net site. PHP files are to be saved with the extension .php.

Syntax:

<?php
//statements go here;
?>

<?
//statements go here;
?>

Comments

Single line comment:
- // -> C++ style
- # -> shell script style
Multi-line comment
/*comment line 1
comment line 2*/

Variables

case sensitive (Note that function names [both user defined & predefined] and keywords are not case sensitive.)
preceded by a '$' symbol
variables need not be initialised using declarative statements

Strings

They cannot be concatenated by the '+' operator. You have to use the '.' operator. Eg.: -

<?php
$str = "This is a string";
$str = $str." with some more text";
?>

String is an array. Eg. of getting the first character of a string: -

$str = "This is a test";
$first = $str[0];

Last character of string: -

$last = $str[strlen($str)-1];

Quotation

Strings are to be placed within double quotes or single quotes. When double quotes are used, all C language escape characters work. In single quotes only '\' & '\\' work.Eg.:

<?php
$name = "Subhash";
echo "$name is a GREAT boy";
echo '$name is a GREAT boy';
?>

The result will be:

Subhash is a GREAT boy
$name is a GREAT boy

Output

echo, print and printf() are the key-words and function used for printing the output. The printf() function has the same syntax as in C. Here is a full example:

<HTML>
<BODY>
<?php
echo "<h4>Hello World!</h4>";
?>
</BODY>
</HTML>