The document discusses various PHP array functions such as sizeof(), is_array(), print_r(), array_merge(), array_values(), array_keys(), array_pop(), array_push(), array_shift(), sort(), array_map(), array_walk(), and array_flip(). It provides examples of how each function can be used to access, manipulate, and operate on array elements in PHP.

1. PHP Array Functions

2.  PHP provides various array functions to access and
manipulate the elements of array.
 rray function will save you a lot of time as they are
pre-defined in PHP libraries and all you have to do is
call them to use them.


3.  This function returns the size of the array or the
number of data elements stored in the array.
 It is just like count($arr) method.
sizeof($arr)

4.  <?php
 $lamborghinis = array("Urus", "Huracan",
"Aventador");
 echo "Size of the array is: ". sizeof($lamborghinis);
 ?>
 Output:
 Size of the array is: 3

5.  To check whether the provided data is in form of an array,
we can use the is_array() function.
 <?php
 $lamborghinis = array("Urus", "Huracan", "Aventador"); //
using ternary operator
 echo is_array($lamborghinis) ? 'Array' : 'not an Array';
$mycar = "Urus"; // using ternary operator
 echo is_array($mycar) ? 'Array' : 'not an Array';
 ?>
 Output:
 Array
 not an Array
is_array($arr)

6.  Although this is not an array function, but it deserves
a special mention here, as we can use this function to
print the array in the most descriptive way possible.
 This function prints the complete representation of
the array, along with all the keys and values.
print_r($arr)

7.  <?php
 $lamborghinis = array("Urus", "Huracan", "Aventador");
 print_r($lamborghinis);
 ?>
 Output:
 Array
 (
 [0] => "Urus"
 [1] => "Huracan"
 [2] => "Aventador"
 )

8.  If you want to combine two different arrays into a
single array, you can do so using this function.
 It doesn't matter whether the arrays to be combined
are of same type(indexed, associative etc)
 or different types, using this function we can combine
them into one single array.
array_merge($arr1, $arr2)

9.  <?php
 $hatchbacks = array( "Suzuki" => "Baleno",
 "Skoda" => "Fabia",
 "Hyundai" => "i20",
 "Tata" => "Tigor" ); // friends who own the above cars
$friends = array("Vinod", "Javed", "Navjot",
"Samuel"); // let's merge the two arrays into one
$merged = array_merge($hatchbacks, $friends);
print_r($merged);
 ?>

10.  Output:
 Array
 (
 [Suzuki] => Baleno
 [Skoda] => Fabia
 [Hyundai] => i20
 [Tata] => Tigor
 [0] => Vinod
 [1] => Javed
 [2] => Navjot
 [3] => Samuel
 )

11.  In an array, data is stored in form of key-value pairs,
where key can be numerical(in case of indexed array)
or user-defined strings(in case of associative array)
and values.
 If we want to take all the values from our array,
without the keys, and store them in a separate array,
then we can use array_values() function.
array_values($arr)

12.  <?php
 $hatchbacks = array(
 "Suzuki" => "Baleno",
 "Skoda" => "Fabia",
 "Hyundai" => "i20",
 "Tata" => "Tigor"
 ); // friends who own the above cars
 $friends = array("Vinod", "Javed", "Navjot", "Samuel"); //
let's merge the two arrays into one
 $merged = array_merge($hatchbacks, $friends); //getting
only the values
 $merged = array_values($merged);
 print_r($merged);
 ?>

13.  Output:
 Array
 (
 [0] => Baleno
 [1] => Fabia
 [2] => i20
 [3] => Tigor
 [4] => Vinod
 [5] => Javed
 [6] => Navjot
 [7] => Samuel
 )

14.  extract just the keys from an array. Let's use this
function to extract the keys from the array $merged.
array_keys($arr)

15.  <?php
 //getting only the keys
 $keys = array_values($merged);
 print_r($keys);
 ?>

16.  Output:
 Array (
 [0] => Suzuki
 [1] => Skoda
 [2] => Hyundai
 [3] => Tata
 [4] => 0
 [5] => 1
 [6] => 2
 [7] => 3
 )

17.  This function removes the last element of the array.
 Hence it can be used to remove one element from the
end.
array_pop($arr)

18.  <?php
 $lamborghinis = array("Urus", "Huracan", "Aventador"); //
removing the last element array_pop($lamborghinis);
 print_r($lamborghinis);
 ?>
 Output:
 Array (
 [0] => Urus
 [1] => Huracan
 )

19.  This function is the opposite of
the array_pop() function.
 This can be used to add a new element at the end of
the array.
array_push($arr, $val)

20.  <?php
 $lamborghinis = array("Urus", "Huracan", "Aventador"); //
adding a new element at the end
array_push($lamborghinis, "Estoque");
print_r($lamborghinis);
 ?>
 Output:
 Array (
 [0] => Urus
 [1] => Huracan
 [2] => Aventador
 [3] => Estoque
 )

21.  This function can be used to remove/shift the first
element out of the array.
 So, it is just like array_pop() function but different in
terms of the position of the element removed.
array_shift($arr)

22.  <?php
 $lamborghinis = array("Urus", "Huracan",
"Aventador"); // removing the first element
array_shift($lamborghinis);
 print_r($lamborghinis);
 ?>

23.  Output:
 Array (
 [0] => Huracan
 [1] => Aventador
 )

24.  Similar to this, we have another
function array_unshift($arr, $val) to add a new
value($val) at the start of the array(as the first
element).

25.  This function sorts the array elements in ascending
order. In case of a string value array, values are sorted
in ascending alphabetical order.
 Some other sorting functions
are: asort(), arsort(), ksort(), krsort() and rsort().
sort($arr)

26.  <?php
 $lamborghinis = array("Urus", "Huracan",
"Aventador", "Estoque"); // sort the array
sort($lamborghinis);
 print_r($lamborghinis);
 ?>

27.  Output:
 Array (
 [0] => Aventador
 [1] => Estoque
 [2] => Huracan
 [3] => Urus )

28.  If you want to perform certain operation on all the values
stored in an array, you can do it by iterating over the array
using a for loop or foreach and performing the required
operation on all the values of the array.
 Or, you can use the function array_map(). All we have to
do is define a separate function to which we will provide
the values stored in the array one by one(one at a time)
and it will perform the operation on the values. Let's have
an example,
array_map('function_name', $arr)

29.  <?php
 function addOne($val)
 { // adding 1 to input value
 return ($val + 1);
 }
 $numbers = array(10, 20, 30, 40, 50); // using
array_map to operate on all the values stored in array
$numbers = array_map('addOne', $numbers);
print_r($numbers)
 ?>

30.  Output:
 Array (
 [0] => 11
 [1] => 21
 [2] => 31
 [3] => 41
 [4] => 51
 )

31.  The function array_walk($arr, 'function_name') works
just like the array_map() function.


32.  This function interchange the keys and the values of a
PHP associative array.
array_flip($arr)

33.  <?
 php $hatchbacks = array( "Suzuki" => "Baleno",
"Skoda" => "Fabia", "Hyundai" => "i20", "Tata" =>
"Tigor" ); // we can directly print the result of array
flipping
 print_r(array_flip($hatchbacks));
 ?>

34.  Output:
 Array (
 [Baleno] => Suzuki
 [Fabia] => Skoda
 [i20] => Hyundai
 [Tigor] => Tata
 )