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PHP Tags
<?php
// Your code goes here
?>
<?
// Short open tag
?>
<?php
// Omit the closing tag in pure PHP file
<?php
$name;
$7days; // False! Can't start with a number
$_7days; // True
$another_name;
$anotherName;Variables
<?php
Comments
// Single line C/C++ style comment
# Another single line Perl style comment
/*
Multi line comment.
Yet another line of comment
*/
//================================
// CATEGORY LARGE FONT
//================================
//--------------------------------
// Sub-Category Smaller Font
//--------------------------------
/*
* This is a detailed explanation
* of something that should require
* several paragraphs of information.
*/<?php
echo vs print
echo($variable);
print($variable); // returns TRUE
// Echo allows us print multiple parameters
echo $variable, 123, $another_var, 'Some string';
<?= 'I love borsch!'; ?>
// Equals
<?php echo 'I love borsch!'; ?><?php
Data Types
Scalar:
- boolean
- integer
- float (aka double)
- string
Compound:
- array
- object
- NULL
- resource
Special:
<?php
Boolean
$foo = TRUE;
$bar = FALSE;
// They're case-insensetive
$spam = TrUe;
$eggs = fAlSe;
<?php
Integer and Float
$integer = 123;
$float = 3.14;
$plus = 3. + .14;
$sub = $plus - 1;
$mul = 2 * $plus;
$div = $plus / 3;<?php
String
$string = 'Personal Home Page';
$double_quotes = "PHP Hypertext Preprocessor";
echo 'PHP' . ' ' . 'WordPress';
echo $string . $double_quotes;
echo strlen($string);<?php
Array
$arr = array(1, 2, 3, 4 ,5);
$another_arr = [1, 2, 3];
echo $arr[1];
echo count($arr);
echo sizeof($another_arr); // Alias of count
$assoc = array('key' => 'val', 'key2' => 'val2',
... ,
'keyN' => 'valN');<?php
NULL
A variable is considered to be null if:
-
it has been assigned the constant NULL.
-
it has not been set to any value yet.
-
it has been unset().
$null = NULL;
echo is_null($undefined_yet);
$variable = 'defined';
echo is_null($variable);
unset($variable);
echo is_null($variable);
$variable = NuLl; // Case-insensetive<?php
Constants
define('DB_NAME', 'creative');
define('DB_USER', 'creative');
define('DB_PASSWORD', '4M6TzwmfUa5vq2wh');
define('DB_HOST', '127.0.0.1');
echo DB_NAME;
<?php
Predefined Variables
echo $_POST['name'];
echo $_GET['email'];$_POST
$_GET
$_REQUEST
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Foreach
foreach ($arr as $val) {
echo $val;
}
foreach ($assoc as $key => $val) {
echo $key . ' = ' . $val;
}
<?php foreach ($arr as $val) : ?>
<!-- HTML goes here... -->
<?php endforeach; ?><?php
Debugging
var_dump($variable);
print_r($variable);
die;
exit('Status message');
exit(1);<?php
Include vs Require
// Emits a warning if it can't find a file
include 'file_to_include.php';
// Emits a fatal error
require 'file_to_include.php';<?php
Tasks
1. Contact form
2. Blog page
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PHP
By sergiienko
PHP
Basics