Programming with php

Creating HTML Forms Pengaturcaraan PHP Managing HTML forms with PHP is a two-step process. First, you create the HTML form itself, using any text or WYSIWYG editor you choose. Then, you create the corresponding PHP script that will receive and process the form data. An HTML form is created using the form tags and various input types. The form tags look as follows: The most important attribute of your form tag is action, which dictates to which page the form data will be sent. The second attribute — method — has its own issues, but post is the value you'll use most frequently. 1

Pengaturcaraan PHP Choosing a Method The method attribute of a form dictates how the data is sent to the handling page. The two options — get and post — refer to the HTTP (Hypertext Transfer Protocol) method to be used. In short, the get method sends the submitted data to the receiving page as a series of name-value pairs appended to the URL. Consider the example shown below: Pengaturcaraan PHP The benefit of using the get method is that the resulting page can be bookmarked in the user's Web browser (since it's a URL). For that matter, you can also click Back in your Web browser to return to a get page, or reload it without problem (neither of which is true for post). Unfortunately, you are limited to how much data can be transmitted via get and it's less secure (since the data is visible). 2

Pengaturcaraan PHP Pengaturcaraan PHP 3

Pengaturcaraan PHP Handling an HTML Form 6

Pengaturcaraan PHP Once you have an HTML form, the next step is to write a bare- bones PHP script to handle it. When we say that this script will be handling the form, we mean that it will do something with the data it receives; that is it will reiterate the data back to the Web browser. The PHP page that receives the form data will assign what the user entered into this form element to a special variable called $_REQUEST['weight']. It is very important that the spelling and capitalization match exactly, as PHP is case-sensitive when it comes to variable names. $_REQUEST['weight'] can then be used like any other variable: printed, used in mathematical computations, concatenated, and so on. Pengaturcaraan PHP Registering Globals In earlier versions of PHP, the register_globals setting was turned on by default. This feature gave PHP an ease of use by automatically turning form inputs into similarly named variables, like $name or $email (as opposed to having to refer to $_REQUEST['name'] and $_REQUEST['email'] first). As of version 4.2 of PHP, the developers behind PHP opted to turn this setting off by default because not relying on this feature improves the security of your scripts. Unfortunately, this also To work around this, there are two had the side effect that a lot of existing options. First, you could turn scripts no longer worked and many beginning programmers were stymied register_globals back on, assuming when they saw blank values in their that you have administrative control form results, error messages, or just over your PHP installation. Second, blank pages. you could start using the superglobal variables, such as $_REQUEST, $_GET, and $_POST. 7

Pengaturcaraan PHP Pengaturcaraan PHP Following the rules outlined before, the data entered into the name form input, which has a name value of name, will be accessible through the variable $_REQUEST['name']. The data entered into the email form input, which has a name value of email, will be accessible through $_REQUEST['email']. The same applies to the entered comments data. Again, the spelling and capitalization of your variables here must exactly match the corresponding name values in the HTML form. 8

Pengaturcaraan PHP Pengaturcaraan PHP $_REQUEST $_REQUEST is a special variable type in PHP, available since version 4.1. It stores all of the data sent to a PHP page through either the GET or POST methods, as well as data accessible in cookies. Blank pages If you see a blank page after submitting the form, first check the HTML source to look for HTML errors, and then confirm that display_errors is on in your PHP configuration. 10

Pengaturcaraan PHP Others way to avoid _$_REQUEST[‘variable’] extract($_GET); extract($_POST); extract($_COOKIE); User can call directly the name of variable like $name without using the method $_POST[“name”]. Managing Magic Quotes 11

Pengaturcaraan PHP In PHP there are two main types of Magic Quotes: magic_quotes_gpc, which applies to form, URL, and cookie data (gpc stands for get, post, cookie); and magic_quotes_runtime, which applies to data retrieved from external files and databases. If Magic Quotes is enabled on your server, you can undo its effect using the stripslashes() function. This function will remove any backslashes found in $var. Pengaturcaraan PHP 13

Pengaturcaraan PHP Pengaturcaraan PHP addslashes() function You can emulate what Magic Quotes does if it's disabled by using the opposite of the stripslashes() function, addslashes(). trim() function When working with strings stemming from forms, it's also a good idea to use the trim() function, which removes excess white spaces from both ends of the value. $name = trim($name); 14

Conditionals Pengaturcaraan PHP Conditionals, like variables, are integral to programming, and most people are familiar with them in some form or another. Dynamic Web pages, as you might imagine, frequently require the use of conditionals to alter a script's behavior according to set criteria. PHP's three primary terms for creating conditionals are if, else, and elseif (which can also be written as two words, else if). Every conditional includes an if clause, as shown here. 15

Pengaturcaraan PHP The if clause in turn can specify an alternate course of action by using else. It can also be written to include another condition and a couple of alternatives by using elseif and else, as in this example. Pengaturcaraan PHP If a condition is true, the code in the following curly braces ({}) will be executed. If not, PHP will continue on. If there is a second condition (after an elseif), that will be checked for truth. The process will continue — you can use as many elseif clauses as you want — until PHP hits an else, which will be automatically executed at that point, or until the conditional terminates without an else. For this reason, it's important that the else always come last and be treated as the default action unless specific criteria (the conditions) 16

In the second example, a new function, isset(), is introduced. This function checks if a variable is set, meaning that it has a value other than NULL. You can also use the comparative and logical operators, listed in the table below, in conjunction with parentheses to make more complicated expressions. SYMBOL MEANING TYPE EXAMPLE $x == $y == is equal to comparison != $x ! = $y is not equal to comparison $x < $y < less than comparison $x > $y > greater than comparison $x <= $y <= less than or equal to comparison $x >= $y >= greater than or equal to comparison ! !$x not logical $x && $y && and logical || or logical $x || $y XOR and not logical $x XOR $y Pengaturcaraan PHP 17

Pengaturcaraan PHP This is a simple and effective way to validate a form input (particularly a radio button, check box, or select). If the user checks either gender radio button, then $_REQUEST['gender'] will have a value, meaning that the condition isset($_REQUEST['gender']) is true. In such a case, the shorthand version of this variable — $gender — is assigned the value of $_REQUEST['gender'], repeating the technique used with $name, $email, and $comments. If the condition is not true, then $gender is assigned the value of NULL, indicating that it has no value. Notice that NULL is not in quotes. Pengaturcaraan PHP 18

Pengaturcaraan PHP This if-elseif-else conditional looks at the value of the $gender variable and prints a different message for each possibility. It's very important to remember that the double equals sign (==) means equals, whereas a single equals sign (=) assigns a value. The distinction is important because the condition $gender == 'M' may or may not be true, but $gender = 'M' will always be true. Pengaturcaraan PHP 19

Pengaturcaraan PHP Switch PHP has another type of conditional, called the switch, best used in place of a long if-elseif-else conditional. The syntax of switch is shown here. The switch conditional compares the value of $variable to the different cases. When it finds a match, the following code is executed, up until the break. If no match is found, the default is executed, assuming it exists (it's optional). The switch conditional is limited in its usage in that it can only check a variable's value for equality against certain cases; more complex conditions cannot be easily checked. Pengaturcaraan PHP 20

Validating Form Data Pengaturcaraan PHP Validating form data requires the use of conditionals and any number of functions, operators, and expressions. One common function to be used is isset(), which tests if a variable has a value (including 0, FALSE, or an empty string, but not NULL). To check that a user typed something into textual elements like name, email, and comments, you can use the empty() function. It checks if a variable has an empty value — an empty string, 0, NULL, or FALSE. 21

Pengaturcaraan PHP The first aim of form validation is ensuring that something was entered or selected in form elements. The second goal is to ensure that submitted data is of the right type (numeric, string, etc.), of the right format (like an email address), or a specific acceptable value (like $gender being equal to either M or F). Next, let's write a new handle_form.php script that makes sure variables have values before they're referenced. Pengaturcaraan PHP 22

Pengaturcaraan PHP strlen() function Another way of validating text inputs is to use the strlen() function to see if more than zero characters were typed. if (strlen($var) > 0) { // $var has a value. } else { // $var does not have a value. } Arrays 25

Pengaturcaraan PHP Unlike strings and numbers (which are scalar variables, meaning they can store only a single value at a time), an array can hold multiple, separate pieces of information. An array is therefore like a list of values, each value being a string or a number or even another array. Arrays are structured as a series of key-value pairs, where one pair is an item or element of that array. For each item in the list, there is a key (or index) associated with it. The resulting structure is not unlike a spreadsheet or database table. PHP supports two kinds of arrays. The first type, called indexed arrays, uses numbers as the keys, as in the first example, the $artists array. As in most programming languages, with indexed arrays, your arrays will begin with the first index at 0, unless you specify the keys explicitly. Key Value 0 Low 1 Aimee Mann 2 Ani DiFranco 3 Spiritualized The second type of array, associative, uses strings as keys as in the following example. The $states array uses the state abbreviation for its keys. Key Value MD Maryland PA Pennsylvania IL Illinois MO Missouri 26

Pengaturcaraan PHP An array follows the same naming rules as any other variable. So offhand, you might not be able to tell that $var is an array as opposed to a string or number. The important syntactical difference has to do with accessing individual array elements. To retrieve a specific value from an array, you refer to the array name first, followed by the key, in square brackets: Pengaturcaraan PHP Because arrays use a different syntax than other variables, printing them can be trickier. First, since an array can contain multiple values, you cannot use a simple print statement. Second, the keys in associative arrays complicate printing them and cause a parse error. 27

Pengaturcaraan PHP To work around this, wrap your array name and key in curly braces when your array uses strings for its keys. Numerically indexed arrays don't have this problem. Superglobal Arrays PHP includes several predefined arrays by default. These are the superglobal variables — $_GET, $_POST, $_SESSION, $_REQUEST, $_SERVER, $_COOKIE, and so forth, added to PHP as of version 4.1. The $_GET variable is where PHP stores all of the variables and values sent to a PHP script via the get method (presumably but not necessarily from an HTML form). $_POST stores all of the data sent to a PHP script from an HTML form that uses the post method. Both of these — along with $_COOKIE — are subsets of $_REQUEST. The superglobals have two benefits over registered global variables. First, they are more secure because they are more precise (they indicate where the variable came from). Second, they are global in scope (hence the name). If you find the syntax of these variables to be confusing, you can use the shorthand technique at the top of your scripts as follows: 28

Pengaturcaraan PHP Pengaturcaraan PHP Earlier versions of PHP The superglobals are new to PHP as of version 4.1. If you are using an earlier version of the language, use $HTTP_POST_VARS instead of $_POST, and $HTTP_GET_VARS instead of $_GET. 30

Creating and Accessing Arrays Pengaturcaraan PHP Creating Arrays Although you can use PHP-generated arrays, there will frequently be times when you want to create your own. There are two primary ways to define your own array. First, you could add one element at a time to build one, as in this example. It's important to understand that if you specify a key and a value already exists indexed with that same key, the new value will overwrite the existing one. In this example, based on the latest assignment, the value of $array['son'] is Michael and that of array[2] is orange. 31

Pengaturcaraan PHP Instead of adding one element at a time, you can use the array() function to build an entire array in one step. This function can be used whether or not you explicitly set the key. Pengaturcaraan PHP On the other hand, if you set the first numeric key value, the added values will be keyed incrementally thereafter, as in this example. Finally, if you want to create an array of sequential numbers you can use the range() function. 32

Accessing Arrays Individual array elements can be accessed by key (e.g., $_POST['email']). This works when you know exactly what the keys are or if you want to refer to only a single element. To access every array element, use the foreach loop. The foreach loop will iterate through every element in $array, assigning each element's value to the $value variable. In this example, you can access both the keys and values. Pengaturcaraan PHP 33

Pengaturcaraan PHP count() or sizeof() function To determine the number of elements in an array, use the count() or sizeof() function (the two are synonymous): $num=count($array); range() function The range() function can also create an array of sequential letters as of PHP 4.1: $alphabet=range('a','z'); Error message in foreach loop If you see an 'Invalid argument supplied for foreach()' error message, that means you are trying to use a foreach loop on a variable that is not an array. Multidimensional Arrays 36

Pengaturcaraan PHP An array's values could be any combination of numbers, strings, and even other arrays. This last option — an array consisting of other arrays — creates a multidimensional array. Multidimensional arrays are much more common than you might expect (especially if you use the superglobals) but remarkably easy to work with. As an example, let's say you have an array called $states and another one called $provinces for Canada, both created by the following definitions. Pengaturcaraan PHP These two arrays could be combined into one multidimensional array as follows: 37

Pengaturcaraan PHP To access the $states array, you refer to $abbr['US'] To access Maryland, use $abbr['US']['MD'] Of course, you can still access multidimensional arrays using the foreach loop, nesting one inside another if necessary. Pengaturcaraan PHP To print out one of these values, surround the whole construct in curly braces: 38

Pengaturcaraan PHP $_POST['interests'] Even if the user selects only one interest, $_POST['interests'] will still be an array because the HTML name for the corresponding input is interests[] (the square brackets make it an array). select menu You can also end up with a multidimensional array by having an HTML form's select menu allow for multiple selections: ‹select name="interests[]" multiple="multiple"› ‹option value="Music"›Music‹/option› ‹option value="Movies"›Movies‹/option› ‹option value="Books"›Books‹/option› ‹option value="Skiing"›Skiing‹/option› ‹option value="Napping"›Napping‹/option› ‹/select› Arrays and Strings 45

Pengaturcaraan PHP Because strings and arrays are so commonly used, PHP has two functions for converting between these two variable types. The key to using and understanding these two functions is the separator and glue relationships. When turning an array into a string, you set the glue — the characters or code that will be inserted between the array values in the generated string. Conversely, when turning a string into an array, you specify the separator, which is the code that delineates between the different elements in the generated array. Let's examine some examples. Pengaturcaraan PHP The $days_array variable is now a five-element array, with Mon indexed at 0, Tue indexed at 1, etc. The $string2 variable is now a comma-separated list of days — Mon, Tue, Wed, Thurs, Fri. 46

Sorting Arrays Pengaturcaraan PHP One of the many advantages arrays have over the other variable types is the ability to sort them. PHP includes several functions you can use for sorting arrays, all simple in syntax. 49

Pengaturcaraan PHP Array (sort/rsort) Sorting Array : sort($pantry_food); - Sort with ascending 0 - 9 rsort($pantry_food); - Sort with Descending 9 – 0 Sort with alphabet alphabet asort($pantry_food); - Sort with ascending A - Z arsort($pantry_food); - Sort with Descending Z – A Pengaturcaraan PHP 50

Pengaturcaraan PHP Pengaturcaraan PHP Array (Adding/Replace) In array, we can add or change content of array example 1 : $fruit = array('banana','papaya'); Cara menambah : <? $fruit[2] = “apple”; print “$fruit[2] ?> The Output apple 52

Pengaturcaraan PHP Array (merging) You also can merge 2 or more array. Example 1 : $pantry = array( 1 => "apples", 2 => "oranges", 3 => "bananas" ); $pantry2 = array( 1 => "potatoes", 2 => "bread", 3 => "tomatoes" ); Pengaturcaraan PHP Array (Merging) Way to combine : <? $pantry_food = array_merge ($pantry, $pantry2); ?> The Output $pantry_food[0] = "apples"; $pantry_food[1] = "oranges"; $pantry_food[2] = "bananas"; $pantry_food[3] = "potatoes"; $pantry_food[4] = "bread"; $pantry_food[5] = "tomatoes"; 53

Pengaturcaraan PHP Array (push) The way to add content at the last of array elemt : example $pantry = array( 1 => "tomatoes", 0 => "oranges", 4 => "bananas", 3 => "potatoes", 2 => "bread" ); array_push($pantry, "apples"); For and While Loops 54

Two types of loops you'll use when managing arrays are for and while. Consider the example of while loop. As long as the condition part of the loop is true, the loop will be executed. Once it becomes false, the loop is stopped. If the condition is never true, the loop will never be executed. The while loop will most frequently be used when retrieving results from a database. Pengaturcaraan PHP The for loop has a more complicated syntax. Upon first executing the loop, the initial expression is run. Then the condition is checked and, if true, the contents of the loop are executed. After execution, the closing expression is run and the condition is checked again. This process continues until the condition is false. Again, the loop will never be executed if the condition is never true. 55

Pengaturcaraan PHP Consider this example. The first time this loop is run, the $i variable is set to the value of 1. Then the condition is checked (is 1 less than or equal to 10?). Since this is true, 1 is printed out (echo $i). Then, $i is incremented to 2 ($i++), the condition is checked, and so forth. The result of this script will be the numbers 1 through 10 printed out. Pengaturcaraan PHP 56

Pengaturcaraan PHP String Manipulation 58

Pengaturcaraan PHP String – “strtok” To take a certain char in the one sentence. The way to take the char can use “,” “.” or anything else Sntax “strtok(“variable",“condition");” Example : <?php $bigstring = "BigBad Wolf"; $firstpart = strtok($bigstring," "); echo "$firstpart"; ?> The output BigBad Pengaturcaraan PHP String – “substr” To take the char based on position. It start from left and counting start by 0 Syntax “substr(“variable",position,length);” Example : <?php $bigstring = "BigBad Wolf"; $example = substr($bigstring,7,4); echo "$example"; ?> The output Wolf 59

Pengaturcaraan PHP String – “eregi/ereg” To search char in variable. Ereg only can search based on case sensitive saja. eregi can search without concern about case-sensitive Syntax “ereg(“condition",“variable");” Syntax “eregi(“condition",“variable");” Pengaturcaraan PHP Example ereg $pattern = "z"; $search_area = "My car goes ZOOM."; $search_result = ereg($pattern,$search_area); if ($search_result){ // print this if there is a true result. echo "Success, the pattern was found!"; } else { // print this if there is a false result. echo "Failure, the pattern was not found!"; } Output Failure, the pattern was not found! 60

Pengaturcaraan PHP Example eregi $pattern = "z"; $search_area = "My car goes ZOOM."; $search_result = eregi($pattern,$search_area); if ($search_result){ // print this if there is a true result. echo "Success, the pattern was found!"; } else { // print this if there is a false result. echo "Failure, the pattern was not found!"; } Output Success, the pattern was found! Pengaturcaraan PHP String – “str_replace” Syntax “str_replace(",","", “variable");” To change anything (like coma) to the anything (like $ dollar sign) Contoh : $cfcost1 = “2,300.00”; $cfcost1 = str_replace(",","","$cfcost1"); Output : 2300.00 61

Pengaturcaraan PHP String – “eregi_replace” To replace char in variable based on search Syntax: eregi_replace(pattern,replacement,search_area); Example $entry = “user@yahoo.com $pattern = “@"; $replacement = “(a)"; $entry = ereg_replace($pattern,$replacement,$entry); echo "$entry"; output user(a)yahoo.com Pengaturcaraan PHP String - “strlen” To count total of char in the variable value Syntax “strlen(“variable")” Example : if(strlen($password) < 6) { print “Jumlah password anda kurang dari 6 aksara”; } else { print “Tahniah”; } 62

Pengaturcaraan PHP String - “strstr” To search certain value in variable Syntax “strstr(“variable“,”word to search”)” Example : $member = “pAB7”; if(strstr($member,”AB”)) { print “Membership anda akan luput tidak lama lagi”; } else { print “Tahniah”; } Pengaturcaraan PHP String - “trim” To clear any blank space in variable at the beginning and end Syntax “trim(“variable“)” Example : $member = “ pAB7 ”; $member = trim($member) print “$member”; Output // print “pAB7”; 63

Pengaturcaraan PHP String - “rtrim” To clear any blank space at the end of variable Syntax “trim(“variable“)” Example : $member = “ pAB7 ”; $member = trim($member) print “$member”; Output // print “ pAB7”; Pengaturcaraan PHP String - “ltrim” To clear any blank space and the begging of variable Syntax “ltrim(“variable“)” Example : $member = “ pAB7 ”; $member = trim($member) print “$member”; Output // print “pAB7 ”; 64

Pengaturcaraan PHP String - “substr_replace” The function same with substr() but it can change the content of variable syntax “substr_replace(“variable“,”Word To Replace”, position, length)” Contoh : $member = “mz02xyz”; $member = substr_replace($member, “03”, 2, 2) print “$member”; Output // print “mz03xyz”; Pengaturcaraan PHP String - “str_repeat” To repeat the sentence follow by total of number required Syntax “str_repeat($string, $n)” : repeat $string $n times Example : echo str_repeat('*', 10); Output // print “***********”; 65

Pengaturcaraan PHP String - “strtoupper” To convert variable to UPPER CASE Syntax “strtoupper(“variable”)” Example : $member = “mzxyz”; $member =strtoupper($member) print “$member”; Output // print “MZXYZ”; Pengaturcaraan PHP String - “strtolower” To convert variable to lowercase Syntax “strtolower(“variable”)” Example : $member = “MZXYZ”; $member =strtoupper($member) print “$member”; Output // print “mzxyz”; 66

Pengaturcaraan PHP String - “strrchr” To get the value of the end of variable with condition Syntax “strrchr(“variable”, “aksara”) ” Example : $file = “file.php”; $ext = $ext = substr(strrchr($file, '.'), 1); print “$ext”; Output // print “php”; Pengaturcaraan PHP String - “wordwrap()” To display variable with the smart appearance which the default can set Syntax “wordwrap(“variable”,”panjang sesuatu ayat”)” Example : $string = “Malaysia negara maju, aman, makmur dan sentoasa”; $string .= “Terdiri daripada 14 buah negeri dan sebuah kerajaan persekutuann”; echo wordwrap($string,75,”<br>”); Output Malaysia negara maju, aman, makmur dan sentoasa Terdiri daripada 14 buah negeri dan sebuah kerajaan persekutuan 67

Random Pengaturcaraan PHP Number (Random) To get random number Example : <?php $random_number = rand( ); echo "$random_number"; ?> The output 221381276 68

Pengaturcaraan PHP Number (Random) To get spcific number in random, we must put a value in the (). Example : <?php $random_number = rand(0,10); echo "$random_number"; ?> The output 0 Pengaturcaraan PHP Password Encrypt – md5 To encrypt the password Example : <?php $passwd = md5($password); echo "$passwd"; ?> The output ddf3rf5765g434dfg676 69

Programming with php

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