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PHP Most of this is from the PHP manual online at:

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What well cover • A short history of php • Parsing • Variables • Arrays • Operators • Functions • Control Structures • External Data Files

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Background • PHP is server side scripting system – PHP stands for "PHP: Hypertext Preprocessor" – Syntax based on Perl Java and C – Very good for creating dynamic content – Powerful but somewhat risky – If you want to focus on one system for dynamic content this is a good one to choose

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History • Started as a Perl hack in 1994 by Rasmus Lerdorf to handle his resume developed to PHP/FI 2.0 • By 1997 up to PHP 3.0 with a new parser engine by Zeev Suraski and Andi Gutmans • Version 5.2.4 is current version rewritten by Zend to include a number of features such as an object model • Current is version 5 • php is one of the premier examples of what an open source project can be

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About Zend • A Commercial Enterprise • Zend provides Zend engine for PHP for free • They provide other products and services for a fee – Server side caching and other optimizations – Encoding in Zends intermediate format to protect source code – IDE-a developers package with tools to make life easier – Support and training services • Zends web site is a great resource

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PHP 5 Architecture • Zend engine as parser Andi Gutmans and Zeev Suraski • SAPI is a web server abstraction layer • PHP components now self contained ODBC Java LDAP etc. • This structure is a good general design for software compare to OSI model and middleware applications

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PHP training in Noida PHP Scripts • Typically file ends in .php--this is set by the web server configuration • Separated in files with the php tag • php commands can make up an entire file or can be contained in html--this is a choice…. • Program lines end in "" or you get an error • Server recognizes embedded script and executes P • Resultphp ismyvarpassed"HellotobrowserWorld" source isnt visible echo myvar /P

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Best PHP Training Institute in Noida Parsing • Weve talk about how the browser can read a text file and process it thats a basic parsing method • Parsing involves acting on relevant portions of a file and ignoring others • Browsers parse web pages as they load • Web servers with server side technologies like php parse web pages as they are being passed out to the browser • Parsing does represent work so there is a cost

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Two Ways • You can embed sections of php inside BODY html:P php myvar "Hello World" echo myvar /BODY • Or youphpcan call html from php: echo "htmlheadtitleHowdy/title …

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What do we know already • Much of what we learned about javascript holds true in php but not all and other languages as well name "bil" echo "Howdy my name is name" echo "What will name be in this line" echo What will name be in this line echo Whats wrong with this line if name "bil" // Hey whats this echo "got a match"

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Variables • Typed by context but one can force type so its loose • Begin with "" unlike javascript • Assigned by value – foo "Bob" bar foo • Assigned by reference this links vars – bar foo • Some are preassigned server and env vars – For example there are PHP vars eg. PHP_SELF HTTP_GET_VARS 00

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phpinfo • The phpinfo function shows the php environment • Use this to read system and server variables setting stored in php.ini versions and modules • Notice that many of these data are in arrays • This is the first script you should write… 00_phpinfo.php

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Variable Variables • Using the value of a variable as the name of a second variable a "hello" a "world" • Thus: echo "a a" • Is the same as: echo "a hello" • But a echoes as "hello"…. 00_hello_world.php

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Operators • Arithmetic + - / and String . • Assignment and combined assignment a 3 a + 5 // sets a to 8 b "Hello " b . "There" // sets b to "Hello There" • Bitwise | – a bXor: Bits that are set in a or b but not both are set. – a Not: Bits that are set in a are not set and vice versa. • Comparison

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Coercion • Just like javascript php is loosely typed • Coercion occurs the same way • If you concatenate a number and string the number becomesa string 17_coercion.php

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Operators: The Movie • Error Control – When this precedes a command errors generated are ignored allows custom messages • Execution ` is similar to the shell_exec function – You can pass a string to the shell for execution: output `ls -al` output shell_exec"ls -al" – This is one reason to be careful about user set variables • Incrementing/Decrementing ++a Increments by one then returns a. a++ Returns a then increments a by one. --a Decrements a by one then returns a. a-- Returns a then decrements a by one.

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Son of the Valley of Operators • Logical a and b And True if both a and b are true. a or b Or True if either a or b is true. a xor b Xor True if either a or b is true but not both. a Not True if a is not true. a b And True if both a and b are true. a || b Or True if either a or b is true. • The two ands and ors have different precedence rules "and" and "or" are lower precedence than "" and "||" • Use parentheses to resolve precedence problems or just to be clearer

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Control Structures • Wide Variety available – if else elseif – while do-while – for foreach – break continue switch – require include require_once include_once

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Control Structures • Mostly parallel to what weve covered already in javascript • if elseif else while for foreach break and continue SAP training in Noida

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Switch • Switch which weve seen is very useful • These two do the same things…. if i 0 echo "i equals 0" elseif i 1 echo "i equals 1" elseif i 2 echo "i equals 2" switch i case 0: echo "i equals 0" break case 1: echo "i equals 1" break case 2: echo "i equals 2" break example from

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Nesting Files • require include include_once require_once are used to bring in an external file • This lets you use the same chunk of code in a number of pages or read other kinds of files into your program • Be VERY careful of using these anywhere close to user input--if a hacker can specify the file to be included that file will execute within your script with whatever rights your script has readfile is a good alternative if you just want the file but dont need to execute it • Yes Virginia remote files can be specified

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Example: A Dynamic Table • I hate writing html tables • You can build one in php • This example uses pictures and builds a table with pictures in one column and captions in another • The captions are drawn from text files • Im using tables but you could use css for placement easily…

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Arrays • You can create an array with the array function or use the explode function this is very useful when reading files into web programs… my_array array1 2 3 4 5 pizza "piece1 piece2 piece3 piece4 piece5 piece6" pieces explode" " pizza • An array is simply a variable representing a keyed list – A list of values or variables – If a variable that var can also be an array – Each variable in the list has a key – The key can be a number or a text label

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Arrays • Arrays are lists or lists of lists or list of lists of lists you get the idea--Arrays can be multi- dimensional • Array elements can be addressed by either by number or by name strings • If you want to see the structure of an array use the print_r function to recursively print an array inside of pre tags PHP and MYSQL Training in noida

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Text versus Keys • Text keys work like number keys well really its the other way around--number keys are just labels • You assign and call them the same way except you have to assign the label to the value or variables eg: echo "my_text_arraythird" my_text_array arrayfirst1 second2 third3 echo "pre" print_rmy_text_array echo "/pre"

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Walking Arrays • Use a loop eg a foreach loop to walk through an array • while loops also work for arrays with numeric keys--just set a variable for the loop and make sure to increment that variable within the loop colors arrayred blue green yellow foreach colors as color echo "Do you like color\n" 05_arrays.php

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05_arrays.php • You cant echo an array directly… – You can walk through an echo or print line by line – You can use print_r this will show you the structure of complex arrays--that output is to the right and its handy for learning the structure of an array Array 1 Array sku A13412 quantity 10 item Whirly Widgets price .50 2 Array sku A43214 quantity 142 item Widget Nuts price .05

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Multidimensional Arrays • A one dimensional array is a list a spreadsheet or other columnar data is two dimensional… • Basically you can make an array of arrays multiD array "fruits" array"myfavorite" "orange" "yuck" "banana" "yum" "apple" "numbers" array1 2 3 4 5 6 "holes" array"first" 5 "second" "third" • The structure can be built array by array or declared with a single statement • You can reference individual elements by nesting: echo "pYes we have no " . multiD"fruits""yuck" . " ok by me./p" • print_r will show the entire structure but don’t forget the pre tags 01a_arrays.php

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Getting Data into arrays • You can directly read data into individual array slots via a direct assignment: pieces5 "poulet resistance" • From a file: – Use the file command to read a delimited file the delimiter can be any unique char: pizza file./our_pizzas.txt – Use explode to create an array from a line within a loop: pieces explode" " pizza

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The Surface • The power of php lies partially in the wealth of functions---for example the 40+ array functions – array_flip swaps keys for values – array_count_values returns an associative array of all values in an array and their frequency – array_rand pulls a random element – array_unique removes duppies – array_walk applies a user defined function to each element of an array so you can dice all of a dataset – count returns the number of elements in an array 08_array_fu.php – array_search returns the key for the first match in

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Using External Data • You can build dynamic pages with just the information in a php script • But where php shines is in building pages out of external data sources so that the web pages change when the data does • Most of the time people think of a database like MySQL as the backend but you can also use text or other files LDAP pretty much anything….

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Standard data files • Normally youd use a tab delimited file but you can use pretty much anything as a delimiter • Files get read as arrays one line per slot • Remember each line ends in \n you should clean this up and be careful about white space • Once the file is read you can use explode to break the lines into fields one at a time in a loop….

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Standard data files • You can use trim to clean white space and returns instead of str_replace • Notice that this is building an array of arrays itemsfile"./mydata.txt" foreach items as line line str_replace"\n" "" line line explode"\t" line // do something with line array

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Useful string functions • str_replace • trim ltrim rtrim • implode explode • addslashes stripslashes • htmlentities html_entity_decode htmlspecialchars • striptags

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06_more_arrays.php • This is a simple script to read and process a text file • The data file is tab delimited and has the column titles as the first line of the file • AngularJS training in Noida

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core Php Training in Noida How it works • The script uses the first line to build text labels for the subsequent lines so that the array elements can be called by the text label – If you add a new column this script compensates – Text based arrays are not position dependent… – This script could be the basis of a nice function

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• There are two version of this calling two different datafiles but thats the only

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06a_more_arrays.php • This version shows how to dynamically build a table in the html output PHP Training Institute in Noida

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CakePHP training in noida Alternative syntax • Applies to if while for foreach and switch • Change the opening brace to a colon php • Change the closing brace to an endxxx if a 5: statement echo "a equals 5" php if a 5: echo "..." A is equal to 5 else: php endif echo "a is not 5" endif 07

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