PHP array_slice() Function

The array_slice() is an inbuilt function of PHP and is used to fetch a part of an array by slicing through it, according to the users choice.
Syntax: 

array_slice($array, $start_point, $slicing_range, preserve)

Parameters: This function can take four parameters and are described below:  

1. $array (mandatory): This parameter refers to the original array, we want to slice.
2. $start_point (mandatory): This parameter refers to the starting position of the array from where the slicing need to be performed. It is mandatory to supply this value. If the value supplied is negative, then the function starts slicing from the end of the array, i.e., -1 refers to the last element of the array.
3. $slicing _range (optional): This parameter refers to the range or limit point upto which the slicing is needed to be done. A negative value will indicate the count from the end of the string. Now, this can also be left blank. On leaving blank the function will slice through all the values as mentioned in the starting point right up to the end.
4. preserve (optional): This parameter can take only two boolean parameters, i.e., either True or False. This will tell the function whether to preserve the keys or reset it. True refers to preserve the keys and false refers to reset the keys. False being the default value.

Return Value: As already mentioned this function will return the selected or the sliced parts of the array.
Below program illustrate the array_slice() function in PHP: 

• In this program, we will be passing all the positive parameters along with the True value to preserve the keys. 

PHP

<?php

// PHP program to illustrate the
// array_slice() function

// Input array
$array = array("ram", "krishna", "aakash",
                        "gaurav", "raghav");

// Slice from pos 1 to pos 3
print_r(array_slice($array, 1, 3, true));

?>

Output: 

Array
(
    [1] => krishna
    [2] => aakash
    [3] => gaurav
)

• Now let’s try to observe the output by passing the same values as in above program, but with False as the value of the preserved key. 

PHP

<?php

// PHP program to illustrate the
// array_slice() function

// input array
$array = array("ram", "krishna", "aakash",
                        "gaurav", "raghav");

// Slice from pos 1 to pos 3
print_r(array_slice($array, 1, 3, false));

?>

Output: 

Array
(
    [0] => krishna
    [1] => aakash
    [2] => gaurav
)

• Below program shows what happens when we dont give the range parameter: 

PHP

<?php

// PHP program to illustrate the
// use of array_slice()

// Input array
$array = array("ram", "krishna", "aakash",
                        "gaurav", "raghav");

// Slice from pos 1 to end
print_r(array_slice($array, 1));

?>

Output: 

Array
(
    [0] => krishna
    [1] => aakash
    [2] => gaurav
    [3] => raghav
)

• Below program illustrate the array_slice() function when we pass the negative parameter as our starting position: 

PHP

<?php

// PHP program to illustrate the
// use of array_slice()

// Input array
$array = array("ram", "krishna", "aakash",
                        "gaurav", "raghav");

// Slice from pos 3rd position to
// the end of the array
print_r(array_slice($array, -3));

?>

Output: 

Array
(
    [0] => aakash
    [1] => gaurav
    [2] => raghav
)

• Below program shows what happens when we try to pass the negative parameters as both the starting point and the length or range: 

PHP

<?php

// PHP program to illustrate the
// use of array_slice()

// Input Array
$array = array("ram", "krishna", "aakash",
                        "gaurav", "raghav");

// Slice from pos 1 to end
print_r(array_slice($array, -3, -2, true));

?>

Output: 

Array
(
    [2] => aakash
)

Reference: 
http://php.net/manual/en/function.array-slice.php