outline o what is an array ? o indexed array o associative array o multidimensional array
TRANSCRIPT
Chapter - 3
Arrays
PHP: Hypertext Preprocessor
Outline
o What is an array ?
o Indexed array
o Associative array
o Multidimensional array
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.
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.
What is an array?
In PHP, the array() function is used to
create an array: array();
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
Indexed Arrays
A numeric array stores each array element
with a numeric index.
There are two ways to create indexed
arrays:
Indexed Arrays
1. In the following example the index are automatically
assigned (the index starts at 0):
- $cars = array ("Saab","Volvo","BMW","Toyota");
2. The following example we assign the index manually:]
1. $cars[0]="Saab";
2. $cars[1]="Volvo";
3. $cars[2]="BMW";
4. $cars[3]="Toyota";
$array_name = array(val1, val2, val3,val4,……);
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.";
?>
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];
}
?>
Print_r() Function
Print construction of array as group of
locations and the value stored in it
print_r ($expression [, bool $return = false ] )
Print_r()
<?php
$arr = array(1,2,3,4,5);
Print_r($arr);
?>Array ( [0] => 1 [1] => 2 [2] => 3 [3] => 4 [4] => 5 )
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 ] )
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
?>
Count Function - Example
<?php
$array = array(“M”, ”u”,”n”,”e”,”e”,”r”);
for ($i = 0; $i < count($array); $i++)
{
echo $array[$i];
}
?>
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; }
Foreach - Example
<?php
$x=array("one","two","three");
foreach ($x as $value)
{
echo $value . "<br />";
}
?>
Foreach - Example
<?php
$colors = array('red', 'blue', 'green', 'yellow');
foreach ($colors as $color) {
echo "Do you like $color?\n";
}
?>
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)
Parameter Description
search Required. Specifies the what to search for
array Required. Specifies the array to search
type Optional. If this parameter is set, the in_array() function searches for the search-string and specific type in the array
Note: If the search parameter is a string and the type parameter is set to TRUE, the search is case-sensitive.
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";
}
?>
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.
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,…..);
Associative Arrays
<?php
$arr = array("foo" => "bar", 12 => true);
echo $arr["foo"]; // bar
echo $arr[12]; // 1
?>
Associative Arrays - example
<?php
// This array is the same as ...
array(5 => 43, 32, 56, "b" => 12);
// ...this array
array(5 => 43, 6 => 32, 7 => 56, "b" =>
12);
?>
Associative Arrays - example
<?php
$ages['Peter'] = "32";
$ages['Quagmire'] = "30";
$ages['Joe'] = "34";
echo "Peter is " . $ages['Peter'] . " years
old.";
?>
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 array
unset($arr); // This deletes the whole array
?>
Associative Arrays - example
<?php
$arr = array("somearray" => array(6 => 5, 13 => 9, "a" =
> 42));
echo $arr["somearray"][6]; // 5
echo $arr["somearray"][13]; // 9
echo $arr["somearray"]["a"]; // 42
?>
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 ) );
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"
?>
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/>”}
?>
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; $j++)
{
print ("i$i j$j " . $try[$i][$j] . "<br> ");
}
print ("<br>");
}
?>
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; $j++)
{ print ("i$i j$j " . $try[$i][$j] . "<br> "); }
print ("<br>");
}
?>