Hello Script for PHP
Saturday, March 15th, 2008In the last post I introduced the concept of ‘Hello Script’ - a file that contains the most commonly used elements of a programming language so that it can be used as a cheat sheet when working with that language. I thought I can elaborate on that concept by creating Hello Scripts for all the languages that I am familiar with.
Let’s start with PHP - I already provided this as an example for the last post. Here is the entire PHP Hello Script…
<?php
// Printing(IO)
print "Hello World!\n";
// Variables, concatenation
$name = 'Binny';
$year = 2008;
print "Hello, " . $name . " - welcome to " . $year . "\n";
//If,else conditions
if ($year > 2008) {
print "Welcome to the future - yes, we have flying cars!";
}
else if($year < 2008) {
print "The past - please don't change anything. Don't step on any butterflies. And for the sake of all that's good and holy, stay away from your parents!";
}
else {
print "Anything wrong with your time machine? You have not gone anywhere, kiddo.";
}
print "\n";
// For loop
for($i=0; $i<3; $i++) {
print "$i) Hi there!\n";
}
//Numerical Array, While
$rules = array(
'Do no harm',
'Obey',
'Continue Living'
);
$i = 0;
while($i<count($rules)) {
print "Rule " . ($i+1) . " : " . $rules[$i] . “\n”;
$i++;
}
// Associated array, foreach
$associated = array(
‘hello’ => ‘world’,
‘foo’ => ‘bar’,
‘lorem’ => ‘ipsum’
);
foreach($associated as $key => $value) {
print “$key: $value\n”;
}
// Using Join and Split
$csv_values = explode(’,', “hello,world,how,are,you\n”);
print implode(”:”, $csv_values);
// Function, argument, return, call
function hello($name) {
return “Hello ” . $name;
}
$hello_string = hello(”Binny”);
// One for the OOP fanboys - Class, members, object and stuff.
class Movie {
public $name = ”;
public $rating = 0;
function __construct($name) {
$this->name = $name;
$this->rateMovie();
}
function rateMovie() {
$this->rating = (strlen($this->name) % 10) + 1; //IMDBs rating algorithm. True story!
}
function printMovieDetails() {
print “Movie : {$this->name}\n”;
print “Rating : ” . str_repeat(’*', $this->rating) . “({$this->rating})\n\n”;
}
}
//Create the object
$ncfom = new Movie(”New Country for Old Men”); //It’s a sequel!
$ncfom->printMovieDetails();
// File IO
// File reading, easy method…
$contents = file_get_contents(’Hello.php’);
print “Hello has ” . strlen($contents) . ” chars\n”;
// Writing to a file
$file_handle = fopen(’/tmp/hello.txt’, ‘w’);
fputs($file_handle, “Hello World”);
fclose($file_handle);
// Command Executing
print `ls`; //Execute the command ‘ls’ and print its output
print “\n”;
// Regular Expressions
$string = “Hello World”;
if(preg_match(’/^Hell/’, $string)) print “Yup - its evil\n”;
print preg_replace(’/l([^l])/’, “$1″, $string); //Remove an ‘l’ from both words. Should print ‘Helo Word’
/*
* Specialized code
*/
// Database connectivity(native)
mysql_connect(’localhost’, ‘root’, ”) or die(”Cannot connect to the Database server”);
mysql_select_db(’Data’) or die(’Could not find a database called “Data”‘);
// Executing Query
$sql_handle = mysql_query(’SELECT name,url,description FROM Comment LIMIT 1′) or die(’Query Error: ‘ . mysql_error());
while($row = mysql_fetch_assoc($sql_handle)) {
print “Name : $row[name]\n”;
print “URL : $row[url]\n”;
print “Desc : $row[description]\n\n”;
}
/* Just a note here - if you are going to use PHP with database in a production
* system(and you will, trust me), use a Database abstraction layer rather than
* the above mentioned native methods.
*/
print $_REQUEST['username']; // Method to get the value of the field ‘username’ after a form submit. Will not work at CLI execution
Save this to a file and keep it around for future reference - if you are just starting out with PHP
Coming up next - Python Hello Script.
