PHP – Array functions
PHP has a very comprehensive list of built-in functions to work with arrays. Please take into consideration that working with big and complicated arrays take a lot of memory usage. You can recycle that memory just by destroying the array if you do not need it anymore.
Here are some simple examples of how you can use some of the array functions in the list below.
PHP Code:
<?php
$file_list = array(
"index" => "home_page.php",
"article" => "article_page.php",
"about" => "about_page.php",
"contact" => "contact_page.php"
);
/*
* Loop through the array and print all the values
*/
if(is_array($file_list)){
foreach($file_list as $file){ // iterate files
echo $file . "<br />";
}
}
/*
* If about key exists inside our array, get his value
*/
$key = "about";
if(array_key_exists($key, $file_list) ){
echo "This is the file that contains the about template: " .$file_list[$key];
}
/*
* Join two arrays into one array and then count all his elements and print them.
*/
$image_list = array(
"favicon" => "favicon.png",
"header" => "header.png",
"footer" => "footer.png"
);
$all_files = array_merge($file_list, $image_list);
echo "The new created array has ". count($all_files) ." items.<br />";
echo "<pre>";
print_r($all_files); // print_r is a very usefull function used for debugging
echo "</pre>";
?>
Here is a very extensive list with some other useful functions to play around with arrays in PHP.
| Array function | Description |
|---|---|
| is_array | Finds whether a variable is an array |
| explode | Split a string by a delimiter and returns an array |
| implode | Join array elements with a string |
| split | Split string into array by regular expression (deprecated) |
| preg_split | Split string by a regular expression |
| unset | Destroys the specified variables. |
| array_change_key_case | Changes the case of all keys in an array |
| array_chunk | Split an array into chunks |
| array_column | Return the values from a single column in the input array |
| array_combine | Creates an array by using one array for keys and another for its values |
| array_count_values | Counts all the values of an array |
| array_diff_assoc | Computes the difference of arrays with additional index check |
| array_diff_key | Computes the difference of arrays using keys for comparison |
| array_diff_uassoc | Computes the difference of arrays with additional index check which is performed by a user supplied callback function |
| array_diff_ukey | Computes the difference of arrays using a callback function on the keys for comparison |
| array_diff | Computes the difference of arrays |
| array_fill_keys | Fill an array with values, specifying keys |
| array_fill | Fill an array with values |
| array_filter | Filters elements of an array using a callback function |
| array_flip | Exchanges all keys with their associated values in an array |
| array_intersect_assoc | Computes the intersection of arrays with additional index check |
| array_intersect_key | Computes the intersection of arrays using keys for comparison |
| array_intersect_uassoc | Computes the intersection of arrays with additional index check, compares indexes by a callback function |
| array_intersect_ukey | Computes the intersection of arrays using a callback function on the keys for comparison |
| array_intersect | Computes the intersection of arrays |
| array_key_exists | Checks if the given key or index exists in the array |
| array_key_first | Gets the first key of an array |
| array_key_last | Gets the last key of an array |
| array_keys | Return all the keys or a subset of the keys of an array |
| array_map | Applies the callback to the elements of the given arrays |
| array_merge_recursive | Merge one or more arrays recursively |
| array_merge | Merge one or more arrays |
| array_multisort | Sort multiple or multi-dimensional arrays |
| array_pad | Pad array to the specified length with a value |
| array_pop | Pop the element off the end of array |
| array_product | Calculate the product of values in an array |
| array_push | Push one or more elements onto the end of array |
| array_rand | Pick one or more random keys out of an array |
| array_reduce | Iteratively reduce the array to a single value using a callback function |
| array_replace_recursive | Replaces elements from passed arrays into the first array recursively |
| array_replace | Replaces elements from passed arrays into the first array |
| array_reverse | Return an array with elements in reverse order |
| array_search | Searches the array for a given value and returns the first corresponding key if successful |
| array_shift | Shift an element off the beginning of array |
| array_slice | Extract a slice of the array |
| array_splice | Remove a portion of the array and replace it with something else |
| array_sum | Calculate the sum of values in an array |
| array_udiff_assoc | Computes the difference of arrays with additional index check, compares data by a callback function |
| array_udiff_uassoc | Computes the difference of arrays with additional index check, compares data and indexes by a callback function |
| array_udiff | Computes the difference of arrays by using a callback function for data comparison |
| array_uintersect_assoc | Computes the intersection of arrays with additional index check, compares data by a callback function |
| array_uintersect_uassoc | Computes the intersection of arrays with additional index check, compares data and indexes by separate callback functions |
| array_uintersect | Computes the intersection of arrays, compares data by a callback function |
| array_unique | Removes duplicate values from an array |
| array_unshift | Prepend one or more elements to the beginning of an array |
| array_values | Return all the values of an array |
| array_walk_recursive | Apply a user function recursively to every member of an array |
| array_walk | Apply a user supplied function to every member of an array |
| array | Create an array |
| arsort | Sort an array in reverse order and maintain index association |
| asort | Sort an array and maintain index association |
| compact | Create array containing variables and their values |
| count | Count all elements in an array, or something in an object |
| current | Return the current element in an array |
| each | Return the current key and value pair from an array and advance the array cursor |
| end | Set the internal pointer of an array to its last element |
| extract | Import variables into the current symbol table from an array |
| in_array | Checks if a value exists in an array |
| key_exists | Alias of array_key_exists |
| key | Fetch a key from an array |
| krsort | Sort an array by key in reverse order |
| ksort | Sort an array by key |
| list | Assign variables as if they were an array |
| natcasesort | Sort an array using a case insensitive “natural order” algorithm |
| natsort | Sort an array using a “natural order” algorithm |
| next | Advance the internal pointer of an array |
| pos | Alias of current |
| prev | Rewind the internal array pointer |
| range | Create an array containing a range of elements |
| reset | Set the internal pointer of an array to its first element |
| rsort | Sort an array in reverse order |
| shuffle | Shuffle an array |
| sizeof | Alias of count |
| sort | Sort an array |
| uasort | Sort an array with a user-defined comparison function and maintain index association |
| uksort | Sort an array by keys using a user-defined comparison function |
| usort | Sort an array by values using a user-defined comparison function |
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