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Introduction> <Variable and Type Related Extensions
[edit] Last updated: Fri, 10 Feb 2012

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Arrays

  • Introduction
  • Installing/Configuring
  • Predefined Constants
  • Sorting Arrays
  • Array Functions
    • array_change_key_case — Changes all keys in an array
    • array_chunk — Split an array into chunks
    • 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_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 two 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 entries 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 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 a 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 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 — 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 array 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


Introduction> <Variable and Type Related Extensions
[edit] Last updated: Fri, 10 Feb 2012
 
add a note add a note User Contributed Notes Arrays
fo dot q dot who at gmail dot com 06-Apr-2011 06:37
Just another way to pass a multidimensional php array to a js array, but i think a cool one so I decided to put this on here.

<?php

function array_print($item, $key, $array_name)
{
    if(
is_array($item)){
       
$array_name = $array_name."['".$key."']";
        echo
$array_name ."= Array();". "";
       
php_array_to_js_array($item, $array_name);
    }else{
        echo
$array_name."['".$key."'] = \"".$item."\";";
    }
}

function
php_array_to_js_array($array, $array_name){
   
array_walk($array, 'array_print', $array_name);
}

?>
<script type="text/javascript" defer="defer">
<?php
       
echo "js_array = Array();";
       
php_array_to_js_array($array, "js_array");
       
?>
</script>

there is not much to say about that, its simple and understandable, i think... if not just email me. Have a nice day pplz !!

Patrick F.
info at curtinsNOSPAMcreations dot com 05-Nov-2010 08:49
Another way to create a multidimensional array that looks a lot cleaner is to use json_decode.  (Note that this probably adds a touch of overhead, but it sure does look nicer.)  You can of course add as many levels and as much formatting as you'd like to the string you then decode.  Don't forget that json requires " around values, not '!!  (So, you can't enclose the json string with " and use ' inside the string.)

As an example:

<?php
    $myarray
['blah'] = json_decode('[
        {"label":"foo","name":"baz"},
        {"label":"boop","name":"beep"}
    ]'
,true);

print_r($myarray)
?>
returns:

Array
(
    [blah] => Array
        (
            [0] => Array
                (
                    [label] => foo
                    [name] => baz
                )
 
            [1] => Array
                (
                    [label] => boop
                    [name] => beep
                )
        )
)
dragos dot rusu at NOSPAM dot bytex dot ro 07-Mar-2010 07:15
If an array item is declared with key as NULL, array key will automatically be converted to empty string '', as follows:

<?php
$a
= array(
   
NULL => 'zero',
   
1    => 'one',
   
2    => 'two');

// This will show empty string for key associated with "zero" value
var_dump(array_keys($a));

// Array elements are shown
reset($a);
while(
key($a) !== NULL )
{
  echo
key($a) . ": ".current($a) . "<br>";// PHP_EOL
 
next($a);
}

// Array elements are not shown
reset($a);
while(
key($a) != NULL ) // '' == null   => no iteration will be executed
{
  echo
key($a) . ": ".current($a) . "<br>";// PHP_EOL
 
next($a);
}
John Marc 15-Feb-2010 02:30
Be careful when adding elements to a numeric array.
I wanted to store some info about some items from a database and decided to use the record id as a key.

<?php
$key
=3000000000;
$DATA[$key]=true;
?>

This will create an array of 30 million elements and chances are, you will use up all memory with these 2 lines

<?php
$key
=3000000000;
$DATA["$key"]=true;
?>

This on the other hand will force the array to be an associative array and will only create the one element
sunear at gmail dot com 04-Aug-2009 12:45
Made this function to delete elements in an array;

<?php

function array_del_elm($input_array, $del_indexes) {
    if (
is_array($del_indexes)) {
       
$indexes = $del_indexes;
    } elseif(
is_string($del_indexes)) {
       
$indexes = explode($del_indexes, " ");
    } elseif(
is_numeric($del_indexes)) {
       
$indexes[0] = (integer)$del_indexes;
    } else return;
   
$del_indexes = null;
   
   
$cur_index = 0;
    if (
sort($indexes)) for($i=0; $i<count($input_array); $i++) {
        if (
$i == $indexes[$cur_index]) {
           
$cur_index++;
            if (
$cur_index == count($indexes)) return $output_array;
            continue;
        }
       
$output_array[] = $input_array[$i];
    }
    return
$output_array;
}

?>

but then i saw the methods of doing the same by Tyler Bannister & Paul, could see that theirs were faster, but had floors regarding deleting multiple elements thus support of several ways of giving parameters. I combined the two methods to this to this:

<?php

function array_del_elm($target_array, $del_indexes) {
    if (
is_array($del_indexes)) {
       
$indexes = $del_indexes;
    } elseif(
is_string($del_indexes)) {
       
$indexes = explode($del_indexes, " ");
    } elseif(
is_numeric($del_indexes)) {
       
$indexes[0] = (integer)$del_indexes;
    } else return;
    unset(
$del_indexes);
   
    for(
$i=0; $i<count($indexes); $i++) {
        unset(
$target_array[$indexes[$i]]);
    }
    return
$target_array;
}

?>

Fast, compliant and functional ;)
Tyler Bannister 11-Jun-2009 08:59
To delete an individual array element use the unset function

For example:

<?PHP
    $arr
= array( "A", "B", "C" );
    unset(
$arr[1] );
   
// now $arr = array( "A", "C" );
?>

Unlink is for deleting files.
thomasdecaux at ebuildy dot com 15-May-2009 03:14
To browse a simple array:

<?php

foreach ($myArray AS $myItem)
{

}

?>

To browse an associative array:

<?php

foreach ($myArray AS $key=>$value)
{

}

?>

http://www.ebuildy.com
macnimble at gmail dot com 27-Mar-2009 07:59
Converting a linear array (like a mysql record set) into a tree, or multi-dimensional array can be a real bugbear. Capitalizing on references in PHP, we can 'stack' an array in one pass, using one loop, like this:

<?php
# array_stack()
# Original idea from:
# http://www.ideashower.com/our_solutions/
#   create-a-parent-child-array-structure-in-one-pass/
function array_stack (&$a, $p = '@parent', $c = '@children')
{
 
$l = $t = array();
  foreach (
$a AS $key => $val):
    if (!
$val[$p]) $t[$key] =& $l[$key];
    else
$l[$val[$p]][$c][$key] =& $l[$key];
   
$l[$key] = (array)$l[$key] + $val;
  endforeach;
  return
$a = array('tree' => $t, 'leaf' => $l);
}

# Example:
$node = array();
$node[1] = array('@parent' => 0, 'title' => 'I am node 1.');
#     ^-----------------------v Link @parent value to key.
$node[2] = array('@parent' => 1, 'title' => 'I am node 2.');
$node[3] = array('@parent' => 2, 'title' => 'I am node 3.');
$node[4] = array('@parent' => 1, 'title' => 'I am node 4.');
$node[5] = array('@parent' => 4, 'title' => 'I am node 5.');

array_stack($node);

$node['leaf'][1]['title'] = 'I am node one.';
$node['leaf'][2]['title'] = 'I am node two.';
$node['leaf'][3]['title'] = 'I am node three.';
$node['leaf'][4]['title'] = 'I am node four.';
$node['leaf'][5]['title'] = 'I am node five.';

echo
'<pre>',print_r($node['tree'],TRUE),'</pre>';
?>

Note that there's no parameter checking on the array value, but this is only to keep the function size small. One could easily a quick check in there to make sure the $a parameter was in fact an array.

Hope you find it useful. Huge thanks to Nate Weiner of IdeaShower.com for providing the original function I built on.
andyd273 at gmail dot com 24-Feb-2009 02:12
A small correction to Endel Dreyer's PHP array to javascript array function. I just changed it to show keys correctly:

            function array2js($array,$show_keys)
            {
                $dimensoes = array();
                $valores = array();
              
                $total = count ($array)-1;
                $i=0;
                foreach($array as $key=>$value){
                    if (is_array($value)) {
                        $dimensoes[$i] = array2js($value,$show_keys);
                        if ($show_keys) $dimensoes[$i] = '"'.$key.'":'.$dimensoes[$i];
                    } else {
                        $dimensoes[$i] = '"'.addslashes($value).'"';
                        if ($show_keys) $dimensoes[$i] = '"'.$key.'":'.$dimensoes[$i];
                    }
                    if ($i==0) $dimensoes[$i] = '{'.$dimensoes[$i];
                    if ($i==$total) $dimensoes[$i].= '}';
                    $i++;
                }
                return implode(',',$dimensoes);
            }
Endel Dreyer 20-Jan-2009 05:16
Function to convert PHP arrays to JavaScript Array Object:
Useful in some cases.

<?php
function array2js($array,$show_keys=false)
{
   
$dimensoes = array();
   
$valores = array();
   
   
$total = count ($array)-1;
   
$i=0;
    foreach (
$array as $key => $value) {
        if (
is_array($value)) {
           
$dimensoes[$i] = array2js($value,$show_keys);
        } else {
           
$dimensoes[$i] = '"'.addslashes($value).'"';
            if (
$show_keys) '"'.$key.'":'.$dimensoes[$i];
        }
        if (
$i==0) $dimensoes[$i] = '['.$dimensoes[$i];
        if (
$i==$total) $dimensoes[$i].= ']';
       
$i++;
    }
    return
implode(',',$dimensoes);
}
?>
Anonymous 26-Nov-2008 11:36
@jorge at andrade dot cl
This variant is faster:
<?php
function array_avg($array,$precision=2){
    if(!
is_array($array))
        return
'ERROR in function array_avg(): this is a not array';

    foreach(
$array as $value)
        if(!
is_numeric($value))
            return
'ERROR in function array_avg(): the array contains one or more non-numeric values';
   
   
$cuantos=count($array);
  return
round(array_sum($array)/$cuantos,$precision);
}
?>
jorge at andrade dot cl 12-Nov-2008 01:03
To calculate the average of a array

<?php
function array_avg($array,$precision="2"){
   
$a=0;
    if(
is_array($array)){
        foreach(
$array as $value):
            if(!
is_numeric($value)){
               
$a++;
            }
        endforeach;
        if(
$a==0){
           
$cuantos=count($array);
            return
round(array_sum($array)/$cuantos,$precision);
        }else{
            return
"ERROR in function array_avg(): the array contains one or more non-numeric values";
        }       
    }else{
        return
"ERROR in function array_avg(): this is a not array";
    }
}
?>
alan dot lake at lakeinfoworks dot com 22-Oct-2008 10:46
To delete an array key (and its value) from an array:

<?php
   
function array_delete(&$ary,$key_to_be_deleted)
    {
       
$new = array();
        if(
is_string($key_to_be_deleted)) {
            if(!
array_key_exists($key_to_be_deleted,$ary)) {
                return;
            }
            foreach(
$ary as $key => $value) {
                if(
$key != $key_to_be_deleted) {
                   
$new[$key] = $value;
                }
            }
           
$ary = $new;
        }
        if(
is_array($key_to_be_deleted)) {
            foreach(
$key_to_be_deleted as $del) {
               
array_delete(&$ary,$del);
            }
        }
    }
?>
webmaster at infoproducts dot x10hosting dot com 10-Oct-2008 09:13
New value can also be added to the array as shown below.
$theVariable["google"] = "http//google.com";
or
$theVariable["1"] = "http//google.com";
Jack A 07-Oct-2008 10:14
Note that arrays are not allowed in class constants and trying to do so will throw a fatal error.
contact at greyphoenix dot biz 30-Jun-2008 11:36
<?php
//Creating a multidimensional array

$theVariable = array("Search Engines" =>
array (
   
0=> "http//google.com",
   
1=> "http//yahoo.com",
   
2=> "http//msn.com/"),

"Social Networking Sites" =>
array (
   
0 => "http//www.facebook.com",
   
1 => "http//www.myspace.com",
   
2 => "http//vkontakte.ru",)
);

echo
"The first array value is " . $theVariable['Search Engines'][0];
?>

-- Output--
The first array value is http://google.com
applegrew at rediffmail dot com 28-May-2008 10:23
For newbies like me.

Creating new arrays:-
//Creates a blank array.
$theVariable = array();

//Creates an array with elements.
$theVariable = array("A", "B", "C");

//Creating Associaive array.
$theVariable = array(1 => "http//google.com", 2=> "http://yahoo.com");

//Creating Associaive array with named keys
$theVariable = array("google" => "http//google.com", "yahoo"=> "http://yahoo.com");

Note:
New value can be added to the array as shown below.
$theVariable[] = "D";
$theVariable[] = "E";

 
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