Chapter - 3

1. Chapter - 3 Arrays PHP: Hypertext Preprocessor

2. Outline • What is an array ? • Indexed array • Associative array • Multidimensional array 

3. What is an Array? • An array is a special variable, which can store multiple values in one single variable. • An array can hold many values under a single name, and you can access the values by referring to an index number.

4. What is an array? • However, what if you want to loop through the cars and find a specific one? And what if you had not 3 cars, but 300? • The best solution here is to use an array! • An array can hold all your variable values under a single name. And you can access the values by referring to the array name. • Each element in the array has its own index so that it can be easily accessed.

5. What is an array? • In PHP, the array() function is used to create an array: array();

6. Kind of arrays in PHP • Indexed  array - An array with a numeric index • Associative array - An array where each ID key is associated with a value • Multidimensional array - An array containing one or more arrays

7. Indexed Arrays • A numeric array stores each array element with a numeric index. • There are two ways to create indexed arrays:

8. Indexed Arrays • In the following example the index are automatically assigned (the index starts at 0): - $cars = array ("Saab","Volvo","BMW","Toyota"); • The following example we assign the index manually:] • $cars[0]="Saab"; • $cars[1]="Volvo"; • $cars[2]="BMW"; • $cars[3]="Toyota"; $array_name = array(val1, val2, val3,val4,……);

9. Indexed Arrays - Example <?php$cars[0]="Saab";$cars[1]="Volvo";$cars[2]="BMW";$cars[3]="Toyota"; echo $cars[0] . " and " . $cars[1] . " are Swedish cars."; ?>

10. Indexed Arrays - Example <?php $array = array(1, 2,3,4,5,6,7,8,9); for ($i = 0; $i < 9; $i++)   {     echo “Number : “. $array[$i]; } ?>

11. Print_r() Function • Print construction of array as group of locations and the value stored in it print_r($expression [, bool $return = false ] )

12. Print_r() <?php $arr = array(1,2,3,4,5); Print_r($arr); ?> Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 )

13. Count() Function • This is build in function ,counts all elements in an array, or something in an object. int count ($var [, int $mode = COUNT_NORMAL ] )

14. Count Function - Example <?php$a[0] = 1;$a[1] = 3;$a[2] = 5;$result = count($a); // $result == 3$b[0]  = 7;$b[5]  = 9;$b[10] = 11;$result = count($b); // $result == 3$result = count(null);// $result == 0$result = count(false);// $result == 1?>

15. Count Function - Example <?php $array = array(“M”, ”u”,”n”,”e”,”e”,”r”); for ($i = 0; $i < count($array); $i++)   {     echo  $array[$i]; } ?>

16. Foreach • For every loop iteration, the value of the current array element is assigned to $value (and the array pointer is moved by one) - so on the next loop iteration, you'll be looking at the next array value. foreach ($array as $value)  {  code to be executed;  }

17. Foreach - Example <?php $x=array("one","two","three");foreach ($x as $value)  {  echo $value . "<br />";  } ?>

18. Foreach - Example <?php $colors = array('red', 'blue', 'green', 'yellow');foreach ($colors as $color) {     echo "Do you like $color?\n"; }?>

19. in_array() Function • The in_array() function searches an array for a specific value. • This function returns TRUE if the value is found in the array, or FALSE otherwise. in_array(search,array,type) Note: If the search parameter is a string and the type parameter is set to TRUE, the search is case-sensitive.

20. in_array() Function - Example <?php$os = array("Mac", “W7", “W8", "Linux");if (in_array(“XP", $os)) {    echo "Got XP";}if (in_array(“Mac", $os)) {    echo "Got Mac";} ?>

21. Associative Arrays • An associative array, each ID key is associated with a value. • When storing data about specific named values, a numerical array is not always the best way to do it. • With associative arrays we can use the values as keys and assign values to them.

22. Associative Arrays • $ages = array("Peter"=>32, "Quagmire"=>30, "Joe"=>34);or • $ages['Peter'] = "32";$ages['Quagmire'] = "30";$ages['Joe'] = "34"; $array_name= array($index1=>$val1, $index1=>$val1,…..);

23. Associative Arrays <?php$arr = array("foo" => "bar", 12 => true);echo $arr["foo"]; // barecho $arr[12];    // 1?>

24. Associative Arrays - example <?php// This array is the same as ...array(5 => 43, 32, 56, "b" => 12);// ...this arrayarray(5 => 43, 6 => 32, 7 => 56, "b" => 12);?>

25. Associative Arrays - example <?php$ages['Peter'] = "32";$ages['Quagmire'] = "30";$ages['Joe'] = "34";echo "Peter is " . $ages['Peter'] . " years old.";?>

26. Associative Arrays - example <?php$arr = array(5 => 1, 12 => 2);$arr[] = 56;    // This is the same as $arr[13] = 56;                // at this point of the script$arr["x"] = 42; // This adds a new element to                // the array with key "x"unset($arr[5]); // This removes the element from the arrayunset($arr);    // This deletes the whole array?>

27. Associative Arrays - example <?php$arr = array("somearray" => array(6 => 5, 13 => 9, "a" => 42));echo $arr["somearray"][6];    // 5echo $arr["somearray"][13];   // 9echo $arr["somearray"]["a"];  // 42?>

28. Multidimensional Arrays • In a multidimensional array, each element in the main array can also be an array. And each element in the sub-array can be an array, $myArray = array( array( value1, value2, value3 ), array( value4, value5, value6 ), array( value7, value8, value9 ) );

29. Multidimensional Arrays <?php$fruits = array ( "fruits"  => array ( "a" => "orange", "b" => "banana“,"c" => "apple”),"numbers" => array ( 1, 2,3,4,5,6), "holes"   => array ("first“,5 => "second“,"third”)); echo $fruits["holes"][5];    // prints "second"echo $fruits["fruits"]["a"]; // prints "orange" ?>

30. Multidimensional Arrays <?php $families = array(“capital"=>array(“A“,“B“,“C”),  “small"=>array(“a”, “b”, “c”), “number"=>array(“1“,“2“,”3”)); foreach($families as $value) {foreach($value as $values) {echo $values.” ”;} Echo “<br/>”} ?>

31. Multidimensional Arrays <?php $try[] = array("11", "12", "15", "22", "41", "42"); $try[] = array("6", "7", "16", "17", "22", "23"); $count = count ($try); for ($i=0; $i<$count; $i++) { $countmore=count($try[0]); for ($j=0; $j < $countmore; $j++) { print ("i$ij$j " . $try[$i][$j] . "<br> "); } print ("<br>"); } ?>

32. Multidimensional Arrays <?php $try[] = array("11", "12", "15", "22", "41", "42"); $try[] = array("6", "7", "16", "17", "22", "23"); $count = count ($try); for ($i=0; $i<$count; $i++) { $countmore=count($try[0]); for ($j=0; $j < $countmore; $j++) { print ("i$ij$j " . $try[$i][$j] . "<br> "); } print ("<br>"); } ?>