Introduction to PHP (Hypertxet PreProcessor, HyperText Processor)

Part 2

PHP Arrays and Superglobals

References

· Chapter 8 Introduction to Server-Side Development with PHP of the Text Book Entitled Fundamentals of Web Development, by Randy Connolly and Ricardo Hoar

· PHP 5.6.26, Sept. 16, 2016; http://php.net/

· PHP 5.6.14 Released Oct. 1, 2015

· PHP 5.6.1 Released Oct. 2, 2014, http://php.net/

· PPH Documentation, http://php.net/urlhowto.php

· PHP Language Reference, http://php.net/manual/en/langref.php

PHP Data Types

· Boolean // true, false

· Integer // whole numbers

· Float // Decimal numbers

· String // Letters, characters

· Array // A collection of data of various data types

· Object // Instances of classes

Functions

· PHP Built-in

o echo() //Output to HTML

o define() // Define constants

o printf() // Formatted output

· User Defined

o Syntax: function, return

o Calling a function

o Parameters

§ Passing by values

§ Passing by reference

o Variable scopes

PHP Arrays, http://php.net/manual/en/language.types.array.php

An array in PHP is actually an ordered map. A map is a type that associates values to keys. This type is optimized for several different uses; it can be treated as an array, list (vector), hash table (an implementation of a map), dictionary, collection, stack, queue, and probably more. As array values can be other arrays, trees and multidimensional arrays are also possible.

Array Applications

· Using an array as a List

o A group of images

· Using an array as a Sortable Table

o Data Table (row, column): Catalog of Pet (pet_name, ower_name, weight, animal, etc)

o Database Tables (row, column)

· Using an array as a Lookup Table

o Cryptogram generator

· Web database applications

Array, http://php.net/manual/en/function.array.php

Definition of Array

· A data structure that allows the programmer to collect a number of related elements together under a single variable.

PHP Arrays

· Called “Associated Arrays”

· An ordered map which associates each value in the array with a key.

· PHP arrays are like vector, hash table, dictionary, and list collection.

· Can be used like collection classes in other languages

Arrays Key (index)

· Must be either integers or strings, and need not be in sequential

· The default array index starts at 0, 1, 2,.. n

Array Values

· Not restricted to integers and strings

· They can be any object, type, or primitive data supported in PHP

Array Manipulations and Functions (Array Functions, http://php.net/manual/en/ref.array.php)

· Declaration of an array (just name of array)

· Define an array (with values)

· Accessing and editing the array (read values)

· Adding and Deleting Elements

· Swapping keys and values

· Merging array elements

· Sorting

· Determining whether keys and values exist

· Searching the array

· Other Array Functions

o Returning an indexed array

o Reverse ordering

o Search array for a value

Defining and Accessing an Array

$days = array(); // Declare an array

$days = array(“Mon”, “Tue”, “Wed”, “Thu”, “Fri”, “Sat”, “Sun”); // Define the contents

$days = [“Mon”, “Tue”, “Wed”, “Thu”, “Fri”, “Sat”, “Sun”]; // Alternate syntax

Or

$day = array();

$days[0] = “Mon”,

$days[1] = “Tue”,

$days[2] = “Wed”,

Or assigning keys explicitly to array elements

$days = array (1 => “Mon”, 2 =>”Tue”, 3 =>”Wed”, 4 =>”Thu”, 5 => “Fri”, 6=>”Sat”, 7 =>Sun”);

# keys are 1, 2, .., 7

# values are “Mon”, “Tue”, …

Array with strings as keys and integer numbers as values

$salesForecast = array(“Mon” => 100, “Tue” => 200, “Wed” => 40, “Thu” => 100, “Fri” => 200, “Sat” => 250, “Sun” => 350);

# Keys are “Mon”, “Tue”, etc

# Values are 100, 200, etc

echo $salesForecast[“Sun”]; // Output 350

Multidimensional Arrays

$month = array

(

array(“Mon”, “Tue”, “Wed”, “Thu”, “Fri”, “Sat”, “Sun”),

array(“Mon”, “Tue”, “Wed”, “Thu”, “Fri”, “Sat”, “Sun”),

array(“Mon”, “Tue”, “Wed”, “Thu”, “Fri”, “Sat”, “Sun”),
array(“Mon”, “Tue”, “Wed”, “Thu”, “Fri”, “Sat”, “Sun”)

)

echo $month[0][3]; // Output Thu

echo $month[3][3]; // Output Thu

echo $month(3][6]; // Output Sun

Shopping Cart Example

$cart = array();

$cart[] =array(“id” => 37, “title” => “Burial at Orans”, quantity => 1);

$cart[] =array(“id” => 345, “title” => “The Death of Marat”, quantity => 1);

$cart[] =array(“id” => 63, “title” => “Starry Night”, quantity => 1);

echo $cart[2][“title”]; // Outputs Starry night

Iteration through an Array

· for, while, do while – only good for those arrays with sequential integers as index

· For arrays without sequential index (associative arrays)

o Need to use count() function to know the number of elements (length) in an array, then use for, while, etc

o foreach loop

Examples

foreach ($salesForecast as $value){

echo $value . “<br>”;

}

foreach ($salesForecast as key => $value){

echo “day” . $key . “=” . $value . “<br>”;

}

Array Functions, http://php.net/manual/en/ref.array.php

· array_keys($someArray); // Return all the keys or a subset of the keys of the given array

· array_values($someArray); // Return all the values of an array

· array_rand($someArray, $num =1); // Pick or select a random element in an array

· array_reverse($someArray); // Return an array with elements in reverse order

· array_walk($someArray, $callBack, $optionalParam); // Apply a user supplied function to every member (element) of an array

· in_array($needle, $haystack); // Check if a value exist in an array; $needle – value, $haystack - array

· shuffle($someArray); // Shuffle an array

Predefined Superglobals, http://php.net/manual/en/language.variables.superglobals.php

Superglobals // Bulit-in variables that are always available in all scopes

· $GLOBALS // All variables available in global scope (array containing info about the

request and the server)

· $_SERVER // Server and execution environment info

· $_GET // HTTP GET variables (array of query string data passed to the server via

the URL)

· $_POST // HTTP POST variables (array of query string data passed to the server

via the HTTP header)

· $_FILES // HTTP file upload variables (array of file items uploaded to the server)

· $_REQUEST // HTTP request variables (array containing the contents of $_GET,

$_POST, and $_COOKIE)

· $_SESSION // Session variables (array contains session data)

· $_ENV // Environment variables (array) of a server

· $_COOKIEs // Array of Cookie data passed to page via HTTP request

PHP Functions Reference

· echo()

· unset() // Destroy variables

· func_get_args() // get function arguments

· func_num_args() // get function argument count

String Manipulation Functions

· strcmp() // string comparison, case sensitive

· strcasecmp() // string comparison, non case sensitive

· substr() // the sub string

· strlen() // The number of chars in the string

· strops() // The character position

· chop() // Remove all white spaces from its ends

· trim() // remove all white spaces from both ends

· strtolower() // covert to lower case characters

· strtoupper() // convert to upper case characters

Arithmetic Functions

· floor(), ceil(), round(), srand(), rand(), abs(), min(), max()

Ouput Functions

· print()

· printf() // formatted output

PHP Functions

· func_get_args() // http://us3.php.net/manual/en/function.func-get-args.php

· func_num_args()

<!DOCTYPE html>

<!—funct_arguments.php - A trivial example to illustrate a php document -->

<html lang = "en">

<head>

<title> funct_arguments.php </title>

<meta charset = "utf-8" />

</head>

<body>

<?php

function func_dynamic() {

echo “ITC 250/CPET 499 Web Systems: “.func_num_args(). “Number of arguments.<br>”;

$args = func_get_args();

for($i = 0; $i < count($args); $i++{

echo “Passed arguments: {args[$i]} <br>;

}

}

func_dynamic(5, 4, 3, 2, 1 );

?>

</body>

</html>