Using Arrays in PHP

Sabari · #21 (**permalink**) 08-16-2007, 11:05 PM

ArrayIterator::valid

ArrayIterator::valid -- Check whether array contains more entries
Description
bool ArrayIterator::valid ( void )

This function checks if the array contains any more entries.

ArrayIterator::valid() example
<?php
$array = array('1' => 'one');

$arrayobject = new ArrayObject($array);
$iterator = $arrayobject->getIterator();

var_dump($iterator->valid()); //bool(true)

$iterator->next(); // advance to the next item

//bool(false) because there is only one array element
var_dump($iterator->valid());
?>

Sabari · #22 (**permalink**) 08-16-2007, 11:06 PM

ArrayObject::append

ArrayObject::append -- Appends the value
Description
void ArrayObject::append ( mixed newval )

Sabari · #23 (**permalink**) 08-16-2007, 11:07 PM

ArrayObject::__construct

ArrayObject::__construct -- Construct a new array object
Description
ArrayObject ArrayObject::__construct ( mixed input )

This constructs a new array object. The input parameter accepts an array or another ArrayObject.

ArrayObject::__construct() example
<?php
$array = array('1' => 'one',
'2' => 'two',
'3' => 'three');

$arrayobject = new ArrayObject($array);

var_dump($arrayobject);
?>

The above example will output:

object(ArrayObject)#1 (3) { [1]=> string(3) "one" [2]=> string(3) "two" [3]=> string(5) "three" }

Sabari · #24 (**permalink**) 08-16-2007, 11:08 PM

ArrayObject::count

ArrayObject::count -- Return the number of elements in the Iterator
Description
int ArrayObject::count ( void )

Sabari · #25 (**permalink**) 08-16-2007, 11:09 PM

ArrayObject::getIterator

ArrayObject::getIterator -- Create a new iterator from an ArrayObject instance
Description
ArrayIterator ArrayObject::getIterator ( void )

This function will return an iterator from an ArrayObject.

ArrayObject::getIterator() example
<?php
$array = array('1' => 'one',
'2' => 'two',
'3' => 'three');

$arrayobject = new ArrayObject($array);

$iterator = $arrayobject->getIterator();

while($iterator->valid()) {
echo $iterator->key() . ' => ' . $iterator->current() . "\n";

$iterator->next();
}
?>

The above example will output:

1 => one 2 => two 3 => three

Sabari · #26 (**permalink**) 08-16-2007, 11:09 PM

ArrayObject::offsetExists

ArrayObject::offsetExists -- Returns whether the requested $index exists
Description
bool ArrayObject::offsetExists ( mixed index )

Sabari · #27 (**permalink**) 08-16-2007, 11:10 PM

ArrayObject::offsetGet

ArrayObject::offsetGet -- Returns the value at the specified $index
Description
bool ArrayObject::offsetGet ( mixed index )

Sabari · #28 (**permalink**) 08-16-2007, 11:11 PM

ArrayObject::offsetSet

ArrayObject::offsetSet -- Sets the value at the specified $index to $newval
Description
void ArrayObject::offsetSet ( mixed index, mixed newval )

Sabari · #29 (**permalink**) 08-16-2007, 11:11 PM

ArrayObject::offsetUnset

ArrayObject::offsetUnset -- Unsets the value at the specified $index
Description
void ArrayObject::offsetUnset ( mixed index )

Sabari · #30 (**permalink**) 08-16-2007, 11:12 PM

CachingIterator::hasNext

CachingIterator::hasNext -- Check whether the inner iterator has a valid next element
Description
bool CachingIterator::hasNext ( void )

Sabari · #31 (**permalink**) 08-16-2007, 11:13 PM

CachingIterator::next

CachingIterator::next -- Move the iterator forward
Description
void CachingIterator::next ( void )

Sabari · #32 (**permalink**) 08-16-2007, 11:14 PM

CachingIterator::rewind

CachingIterator::rewind -- Rewind the iterator
Description
void CachingIterator::rewind ( void )

Sabari · #33 (**permalink**) 08-16-2007, 11:14 PM

CachingIterator::__toString

CachingIterator::__toString -- Return the string representation of the current element
Description
string CachingIterator::__toString ( void )

Jeyaseelansarc · #34 (**permalink**) 08-17-2007, 12:14 AM

The array_map() function sends each value of an array to a user-made function, and returns an array with new values, given by the user-made function.
Applies the callback to the elements of the given arrays.

Syntax

Quote:

array array_map ( callback callback, array arr1 [, array ...] )

Description

array_map() returns an array containing all the elements of arr1 after applying the callback function to each one. The number of parameters that the callback function accepts should match the number of arrays passed to the array_map()

Example

PHP Code:

  <?php

function cube($n)

{

    return($n * $n * $n);

}

 
$a = array(1, 2, 3, 4, 5);

$b = array_map("cube", $a);

print_r($b);

?>

This makes $b have:

Code:

Array
(
    [0] => 1
    [1] => 8
    [2] => 27
    [3] => 64
    [4] => 125
)

Sabari · #35 (**permalink**) 08-18-2007, 03:18 AM

Using foreach on Arrays

foreach is a great function that most people miss in the beginning when coding PHP. That's really stupid because it's a useful function for handling with Arrays. Look at this piece of code and I will explain what it does after the code:

$myArray = Array("firstname" => "sabari",
"lastname" => "nathan",
"age" => 28);

foreach($myArray as $key => $value)
{
echo $key . "-". $value . "<br/>";
}

This little neat piece of code will output the keys with the associated value. So the output will be something like this:

Output:

firstname - sabari
lastname - nathan
age - 28

Sabari · #36 (**permalink**) 08-18-2007, 04:13 AM

array_chunk

array_chunk — Split an array into chunks

array_chunk() example
<?php
$input_array = array('a', 'b', 'c', 'd', 'e');
print_r(array_chunk($input_array, 2));
print_r(array_chunk($input_array, 2, true));
?>

The above example will output:
Array
(
[0] => Array
(
[0] => a
[1] => b
)

[1] => Array
(
[0] => c
[1] => d
)

[2] => Array
(
[0] => e
)

)
Array
(
[0] => Array
(
[0] => a
[1] => b
)

[1] => Array
(
[2] => c
[3] => d
)

[2] => Array
(
[4] => e
)

)

Sabari · #37 (**permalink**) 08-18-2007, 04:19 AM

array_merge_recursive

array_merge_recursive — Merge two or more arrays recursively

<?php
$ar1 = array("color" => array("favorite" => "red"), 5);
$ar2 = array(10, "color" => array("favorite" => "green", "blue"));
$result = array_merge_recursive($ar1, $ar2);
print_r($result);
?>

The above example will output:

Array
(
[color] => Array
(
[favorite] => Array
(
[0] => red
[1] => green
)

[0] => blue
)

[0] => 5
[1] => 10
)

Sabari · #38 (**permalink**) 08-18-2007, 04:24 AM

array_multisort

array_multisort — Sort multiple or multi-dimensional arrays

Example: Sorting multiple arrays

<?php
$ar1 = array("10", 100, 100, "a");
$ar2 = array(1, 3, "2", 1);
array_multisort($ar1, $ar2);

var_dump($ar1);
var_dump($ar2);
?>

The above example will output:

array(4) {
[0]=> string(2) "10"
[1]=> string(1) "a"
[2]=> int(100)
[3]=> int(100)
}
array(4) {
[0]=> int(1)
[1]=> int(1)
[2]=> string(1) "2"
[3]=> int(3)
}

Sabari · #39 (**permalink**) 08-18-2007, 04:28 AM

array_walk

array_walk — Apply a user function to every member of an array

Example: array_walk() example

<?php
$fruits = array("d" => "lemon", "a" => "orange", "b" => "banana", "c" => "apple");

function test_alter(&$item1, $key, $prefix)
{
$item1 = "$prefix: $item1";
}

function test_print($item2, $key)
{
echo "$key. $item2<br />\n";
}

echo "Before ...:\n";
array_walk($fruits, 'test_print');

array_walk($fruits, 'test_alter', 'fruit');
echo "... and after:\n";

array_walk($fruits, 'test_print');
?>

The above example will output:

Before ...:
d. lemon
a. orange
b. banana
c. apple
... and after:
d. fruit: lemon
a. fruit: orange
b. fruit: banana
c. fruit: apple

Sabari · #40 (**permalink**) 08-18-2007, 04:30 AM

array_walk_recursive

array_walk_recursive — Apply a user function recursively to every member of an array

Example: array_walk_recursive() example

<?php
$sweet = array('a' => 'apple', 'b' => 'banana');
$fruits = array('sweet' => $sweet, 'sour' => 'lemon');

function test_print($item, $key)
{
echo "$key holds $item\n";
}

array_walk_recursive($fruits, 'test_print');
?>

The above example will output:

a holds apple
b holds banana
sour holds lemon

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