From http://www.w3schools.com (Copyright Refsnes Data)

PHP array_slice() Function

Definition and Usage

The array_slice() function returns selected parts of an array.

array_slice(array,start,length,preserve)

Parameter	Description
array	Required. Specifies an array
start	Required. Numeric value. Specifies where the function will start the slice. 0 = the first element. If this value is set to a negative number, the function will start slicing that far from the last element. -2 means start at the second last element of the array.
length	Optional. Numeric value. Specifies the length of the returned array. If this value is set to a negative number, the function will stop slicing that far from the last element. If this value is not set, the function will return all elements, starting from the position set by the start-parameter.
preserve	Optional. Possible values: true - Preserve keys false - Default - Reset keys

Note: If the array have string keys, the returned array will allways preserve the keys. (See example 4)

<?php
$a=array(0=>"Dog",1=>"Cat",2=>"Horse",3=>"Bird");
print_r(array_slice($a,1,2));
?>

The output of the code above will be:

Array ( [0] => Cat [1] => Horse )

With a negative start parameter:

<?php
$a=array(0=>"Dog",1=>"Cat",2=>"Horse",3=>"Bird");
print_r(array_slice($a,-2,1));
?>

The output of the code above will be:

Array ( [0] => Horse )

With the preserve parameter set to true:

<?php
$a=array(0=>"Dog",1=>"Cat",2=>"Horse",3=>"Bird");
print_r(array_slice($a,1,2,true));
?>

The output of the code above will be:

Array ( [1] => Cat [2] => Horse )

With string keys:

<?php
$a=array("a"=>"Dog","b"=>"Cat","c"=>"Horse","d"=>"Bird");
print_r(array_slice($a,1,2));
?>

The output of the code above will be:

Array ( [b] => Cat [c] => Horse )