Using arrays with PHP for forms and storing information

Using Arrays with PHP for Forms and Storing Information

2 Objectives In this chapter, you will: Manipulate array elements Explore associative arrays Find and extract elements and values Understand multidimensional arrays Use arrays in Web forms

4PHP Programming with MySQL, 2nd Edition Message Board Example

5 Manipulating Elements (continued) Code examples at: http://zombieguineapigs.com/php

6PHP Programming with MySQL, 2nd Edition Adding and Removing Elements The array_shift() function removes the first element from the beginning of an array – Pass the name of the array whose first element you want to remove The array_unshift() function adds one or more elements to the beginning of an array – Pass the name of an array followed by comma- separated values for each element you want to add

7PHP Programming with MySQL, 2nd Edition Adding and Removing Elements from the Beginning of an Array $TopSellers = array( "Chevrolet Impala", "Chevrolet Malibu", "Chevrolet Silverado", "Ford F-Series", "Toyota Camry", "Toyota Corolla", "Nissan Altima", "Honda Accord", "Honda Civic", "Dodge Ram"); array_shift($TopSellers); array_unshift($TopSellers, "Honda CR-V"); echo "<pre>n"; print_r($TopSellers); echo "</pre>n";

8 Adding and Removing Elements

9PHP Programming with MySQL, 2nd Edition Adding and Removing Elements The array_pop() function removes the last element from the end of an array Pass the name of the array whose last element you want to remove The array_push() function adds one or more elements to the end of an array Pass the name of an array followed by comma-separated values for each element you want to add

10PHP Programming with MySQL, 2nd Edition Adding and Removing Elements $HospitalDepts = array( "Anesthesia", "Molecular Biology", "Neurology", "Pediatrics"); array_pop($HospitalDepts); // Removes "Pediatrics" array_push($HospitalDepts, "Psychiatry", "Pulmonary Diseases");

11 Adding and Removing Elements The array_splice() function adds or removes array elements The array_splice() function renumbers the indexes in the array Syntax: array_splice(array_name, start, characters_to_delete, values_to_insert);

12 Adding and Removing Elements Within an Array (continued) To add an element within an array, include a value of 0 as the third argument of the array_splice() function $HospitalDepts = array( "Anesthesia", // first element (0) "Molecular Biology", // second element (1) "Neurology", // third element (2) "Pediatrics"); // fourth element (3) array_splice($HospitalDepts, 3, 0, "Ophthalmology");

13 Adding and Removing Elements To add more than one element within an array, pass the array() construct as the fourth argument of the array_splice() function Separate the new element values by commas $HospitalDepts = array( "Anesthesia", // first element (0) "Molecular Biology", // second element (1) "Neurology", // third element (2) "Pediatrics"); // fourth element (3) array_splice($HospitalDepts, 3, 0, array("Opthalmology", "Otolaryngology"));

14PHP Programming with MySQL, 2nd Edition Adding and Removing Elements Within an Array (continued) Delete array elements by omitting the fourth argument from the array_splice() function $HospitalDepts = array( "Anesthesia", // first element (0) "Molecular Biology", // second element (1) "Neurology", // third element (2) "Pediatrics"); // fourth element (3) array_splice($HospitalDepts, 1, 2);

15 Adding and Removing Elements The unset() function removes array elements and other variables Pass to the unset() function the array name and index number of the element you want to remove To remove multiple elements, separate each index name and element number with commas unset($HospitalDepts[1], $HospitalDepts[2]);

16 Removing Duplicate Elements The array_unique() function removes duplicate elements from an array Pass to the array_unique() function the name of the array from which you want to remove duplicate elements The array_values() and array_unique() functions do not operate directly on an array The array_unique() function renumbers the indexes after removing duplicate values

17 Removing Duplicate Elements $TopSellers = array( "Ford F-Series", "Chevrolet Silverado", "Toyota Camry", "Honda Accord", "Toyota Corolla", "Ford F-Series", "Honda Civic", "Honda CR-V", "Honda Accord", "Nissan Altima", "Toyota Camry", "Chevrolet Impala", "Dodge Ram", "Honda CR-V"); echo "<p>The 2008 top selling vehicles are:</p><p>"; $TopSellers = array_unique($TopSellers); $TopSellers = array_values($TopSellers); for ($i=0; $i<count($ TopSellers); ++$i) { echo "{$TopSellers[$i]}<br />"; } echo "</p>";

18 Removing Duplicate Elements Figure 6-4 Output of an array after removing duplicate values with the array_unique() function

19 Declaring and Initializing Associative Arrays With associative arrays, specify an element’s key by using the array operator (=>) $array_name = array(key=>value, ...);

20 Associative Arrays $Territories[100] = "Nunavut"; $Territories[] = "Northwest Territories"; $Territories[] = "Yukon Territory"; echo "<pre>n"; print_r($Territories); echo "</pre>n"; echo '<p>The $Territories array consists of ', count($Territories), " elements.</p>n";

21 Iterating Through an Array The internal array pointer refers to the currently selected element in an array

22 Iterating Through an Associative Array Figure 6-8 Output of an array without advancing the internal array pointer – See page 325

Iterating Through an Associative Array To fix the issue on slide 22, use this code: foreach ($ProvincialCapitals as $Capital) { echo “The capital of : . key($ProvincialCapitals) . “ is $Capital<br />n”; next($ProvincialCapitals); 23

Iterating Through an Associative Array 24

25 Finding and Extracting Elements and Values • One of the most basic methods for finding a value in an array is to use a looping statement to iterate through the array until you find the value • Rather than write custom code to find a value, use the in_array() and array_search() functions to determine whether a value exists in an array

26 Determining if a Value Exists The in_array() function returns a Boolean value of true if a given value exists in an array The array_search() function determines whether a given value exists in an array and: Returns the index or key of the first matching element if the value exists, or Returns FALSE if the value does not exist if (in_array("Neurology", $HospitalDepts)) echo "<p>The hospital has a Neurology department.</p>";

27 Determining if a Key Exists The array_key_exists() function determines whether a given index or key exists You pass two arguments to the array_key_exists() function: The first argument represents the key to search for The second argument represents the name of the array in which to search

28 Determining if a Key Exists $ScreenNames["Dancer"] = "Daryl"; $ScreenNames["Fat Man"] = "Dennis"; $ScreenNames["Assassin"] = "Jennifer"; if (array_key_exists("Fat Man", $ScreenNames)) echo "<p>{$ScreenNames['Fat Man']} is already 'Fat Man'.</p>n"; else { $ScreenNames["Fat Man"] = "Don"; echo "<p>{$ScreenNames['Fat Man']} is now 'Fat Man'.</p>"; }

29PHP Programming with MySQL, 2nd Edition Returning a Portion of an Array The array_slice() function returns a portion of an array and assigns it to another array The syntax for the array_slice() function is: array_slice(array_name, start, characters_to_return);

30 Returning a Portion of an Array // This array is ordered by sales, high to low. $TopSellers = array("Ford F-Series", "Chevrolet Silverado", "Toyota Camry", "Honda Accord", "Toyota Corolla", "Honda Civic", "Nissan Altima", "Chevrolet Impala", "Dodge Ram", "Honda CR-V"); $FiveTopSellers = array_slice($TopSellers, 0, 5); echo "<p>The five best-selling vehicles for 2008 are:</p>n"; for ($i=0; $i<count($FiveTopSellers); ++$i) { echo "{$FiveTopSellers[$i]}<br />n"; }

31 Returning a Portion of an Array Figure 6-11 Output of an array returned with the array_slice() function

32 Creating Two-Dimensional Indexed Arrays A multidimensional array consists of multiple indexes or keys A two-dimensional array has two sets of indexes or keys

33 Two-Dimensional Indexed Arrays $Gallons = array( 128, // ounces 16, // cups 8, // pints 4 // quarts );

34 Two-Dimensional Indexed Arrays $Ounces = array(1, 0.125, 0.0625, 0.03125, 0.0078125); $Cups = array(8, 1, 0.5, 0.25, 0.0625); $Pints = array(16, 2, 1, 0.5, 0.125); $Quarts = array(32, 4, 2, 1, 0.25); $Gallons = array(128, 16, 8, 4, 1);

35 Two-Dimensional Indexed Arrays $VolumeConversions = array($Ounces, $Cups, $Pints, $Quarts, $Gallons);

36 Two-Dimensional Associative Arrays $Ounces = array("ounces" => 1, "cups" => 0.125, "pints" => 0.0625, "quarts" => 0.03125, "gallons" => 0.0078125); $Cups = array("ounces" => 8, "cups" => 1, "pints" =>0.5, "quarts" => 0.25, "gallons" => 0.0625); $Pints = array("ounces" => 16, "cups" => 2, "pints" =>1, "quarts" => 0.5, "gallons" => 0.125); $Quarts = array("ounces" => 32, "cups" => 4, "pints" =>2, "quarts" => 1, "gallons" => 0.25); $Gallons = array("ounces" => 128, "cups" => 16, "pints" =>8, "quarts" => 4, "gallons" => 1);

37 Two-Dimensional Associative Arrays Figure 6-21 Elements and keys in the $VolumeConversions[ ] array

Using Arrays in Web Forms Store form data in an array by appending an opening and closing ([]) to the value of the name attribute Data from any element with the same value for the name attribute will be appended to an array with that name 38

Using Arrays in Web Forms <form method='post' action='ProcessForm.php'> <p>Enter the first answer: <input type='text' name='answers[]' /></p> <p>Enter the second answer: <input type='text' name='answers[]' /></p> <p>Enter the third answer: <input type='text' name='answers[]' /></p> <input type='submit' name='submit' value='submit' /> </form> 39

Using Arrays in Web Forms if (is_array($_POST['answers')) { $Index = 0; foreach ($_POST['answers'] as $Answer) { ++$Index; echo "The answer for question $Index is '$Answer'<br />n"; } } 40

Using Arrays in Web Forms 41 Figure 6-22 Output of an array posted from a Web form

Associative Forms Array <form method='post' action='ProcessForm.php'> <p>Enter the first answer: <input type='text' name='answers[Question 1]' /></p> <p>Enter the second answer: <input type='text' name='answers[Question 2]' /></p> <p>Enter the third answer: <input type='text' name='answers[Question 3]' /></p> <input type='submit' name='submit' value='submit' /> </form> 42

Using arrays with PHP for forms and storing information

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Using arrays with PHP for forms and storing information