|
Function
|
Explanation
|
Example
|
sizeof($arr)
| This function returns the number of elements in an array.
Use
this function to find out how many elements an array contains; this
information is most commonly used to initialize a loop counter when
processing the array.
| Code:
$data = array("red", "green", "blue");
echo "Array has " . sizeof($data) . " elements";
?>
Output:
Array has 3 elements |
array_values($arr)
| This
function accepts a PHP array and returns a new array containing only
its values (not its keys). Its counterpart is the array_keys()
function.
Use this function to retrieve all the values from an associative array.
| Code:
$data = array("hero" => "Holmes", "villain" => "Moriarty");
print_r(array_values($data));
?>
Output:
Array
(
[0] => Holmes
[1] => Moriarty
) |
array_keys($arr)
| This
function accepts a PHP array and returns a new array containing only
its keys (not its values). Its counterpart is the array_values()
function.
Use this function to retrieve all the keys from an associative array.
| Code:
$data = array("hero" => "Holmes", "villain" => "Moriarty");
print_r(array_keys($data));
?>
Output:
Array
(
[0] => hero
[1] => villain
) |
array_pop($arr)
| This function removes an element from the end of an array.
| Code:
$data = array("Donald", "Jim", "Tom");
array_pop($data);
print_r($data);
?>
Output:
Array
(
[0] => Donald
[1] => Jim
) |
array_push($arr, $val)
| This function adds an element to the end of an array.
| Code:
$data = array("Donald", "Jim", "Tom");
array_push($data, "Harry");
print_r($data);
?>
Output:
Array
(
[0] => Donald
[1] => Jim
[2] => Tom
[3] => Harry
) |
array_shift($arr)
| This function removes an element from the beginning of an array.
| Code:
$data = array("Donald", "Jim", "Tom");
array_shift($data);
print_r($data);
?>
Output:
Array
(
[0] => Jim
[1] => Tom
) |
array_unshift($arr, $val)
| This function adds an element to the beginning of an array.
| Code:
$data = array("Donald", "Jim", "Tom");
array_unshift($data, "Sarah");
print_r($data);
?>
Output:
Array
(
[0] => Sarah
[1] => Donald
[2] => Jim
[3] => Tom
) |
each($arr)
| This
function is most often used to iteratively traverse an array. Each
time each() is called, it returns the current key-value pair and moves
the array cursor forward one element. This makes it most suitable for
use in a loop.
| Code:
$data = array("hero" => "Holmes", "villain" => "Moriarty");
while (list($key, $value) = each($data)) {
echo "$key: $value \n";
}
?>
Output:
hero: Holmes
villain: Moriarty |
sort($arr)
| This
function sorts the elements of an array in ascending order. String
values will be arranged in ascending alphabetical order.
Note: Other sorting functions include asort(), arsort(), ksort(), krsort() and rsort().
| Code:
$data = array("g", "t", "a", "s");
sort($data);
print_r($data);
?>
Output:
Array
(
[0] => a
[1] => g
[2] => s
[3] => t
) |
array_flip($arr)
| The function exchanges the keys and values of a PHP associative array.
Use
this function if you have a tabular (rows and columns) structure in
an array, and you want to interchange the rows and columns.
| Code:
$data = array("a" => "apple", "b" => "ball");
print_r(array_flip($data));
?>
Output:
Array
(
[apple] => a
[ball] => b
) |
array_reverse($arr)
| The function reverses the order of elements in an array.
Use
this function to re-order a sorted list of values in reverse for
easier processing—for example, when you're trying to begin with the
minimum or maximum of a set of ordered values.
| Code:
$data = array(10, 20, 25, 60);
print_r(array_reverse($data));
?>
Output:
Array
(
[0] => 60
[1] => 25
[2] => 20
[3] => 10
) |
array_merge($arr)
| This
function merges two or more arrays to create a single composite
array. Key collisions are resolved in favor of the latest entry.
Use
this function when you need to combine data from two or more arrays
into a single structure—for example, records from two different SQL
queries.
| Code:
$data1 = array("cat", "goat");
$data2 = array("dog", "cow");
print_r(array_merge($data1, $data2));
?>
Output:
Array
(
[0] => cat
[1] => goat
[2] => dog
[3] => cow
) |
array_rand($arr)
| This function selects one or more random elements from an array.
Use
this function when you need to randomly select from a collection of
discrete values—for example, picking a random color from a list.
| Code:
$data = array("white", "black", "red");
echo "Today's color is " . $data[array_rand($data)];
?>
Output:
Today's color is red |
array_search($search, $arr)
| This
function searches the values in an array for a match to the search
term, and returns the corresponding key if found. If more than one
match exists, the key of the first matching value is returned.
Use this function to scan a set of index-value pairs for matches, and return the matching index.
| Code:
$data = array("blue" => "#0000cc", "black" => "#000000", "green" => "#00ff00");
echo "Found " . array_search("#0000cc", $data);
?>
Output:
Found blue |
array_slice($arr, $offset, $length)
| This
function is useful to extract a subset of the elements of an array,
as another array. Extracting begins from array offset $offset and
continues until the array slice is $length elements long.
Use
this function to break a larger array into smaller ones—for example,
when segmenting an array by size ("chunking") or type of data.
| Code:
$data = array("vanilla", "strawberry", "mango", "peaches");
print_r(array_slice($data, 1, 2));
?>
Output:
Array
(
[0] => strawberry
[1] => mango
) |
array_unique($data)
| This function strips an array of duplicate values.
Use
this function when you need to remove non-unique elements from an
array—for example, when creating an array to hold values for a table's
primary key.
| Code:
$data = array(1,1,4,6,7,4);
print_r(array_unique($data));
?>
Output:
Array
(
[0] => 1
[3] => 6
[4] => 7
[5] => 4
) |
array_walk($arr, $func)
| This function "walks" through an array, applying a user-defined function to every element. It returns the changed array.
Use
this function if you need to perform custom processing on every
element of an array—for example, reducing a number series by 10%.
| Code:
function reduceBy10(&$val, $key) {
$val -= $val * 0.1;
}
$data = array(10,20,30,40);
array_walk($data, 'reduceBy10');
print_r($data);
?>
Output:
Array
(
[0] => 9
[1] => 18
[2] => 27
[3] => 36
) |
