array_chunk

(PHP 4 >= 4.2.0, PHP 5, PHP 7)

array_chunk — 将一个数组分割成多个

说明

array array_chunk ( array $input , int $size [, bool $preserve_keys = false ] )

将一个数组分割成多个数组，其中每个数组的单元数目由 size 决定。最后一个数组的单元数目可能会少于 size 个。

参数

input: 需要操作的数组
size: 每个数组的单元数目
preserve_keys: 设为 TRUE ，可以使 PHP 保留输入数组中原来的键名。如果你指定了 FALSE ，那每个结果数组将用从零开始的新数字索引。默认值是 FALSE 。

返回值

得到的数组是一个多维数组中的单元，其索引从零开始，每一维包含了 size 个元素。

错误／异常

如果 size 小于 1，会抛出一个 E_WARNING 错误并返回 NULL 。

范例

Example #1 array_chunk() 例子

  <?php
$input_array  = array( 'a' ,  'b' ,  'c' ,  'd' ,  'e' );
 print_r ( array_chunk ( $input_array ,  2 ));
 print_r ( array_chunk ( $input_array ,  2 ,  true ));
 ?>

以上例程会输出：

Array
(
    [0] => Array
        (
            [0] => a
            [1] => b
        )    [1] => Array
        (
            [0] => c
            [1] => d
        )    [2] => Array
        (
            [0] => e
        ))
Array
(
    [0] => Array
        (
            [0] => a
            [1] => b
        )    [1] => Array
        (
            [2] => c
            [3] => d
        )    [2] => Array
        (
            [4] => e
        ))

参见

array_slice() - 从数组中取出一段

用户评论:

[#1] siddharthundare at gmail dot com [2015-09-28 09:00:14]

<table>
<tr>
<?php $array_chunkdata = array(1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25); $chunk = array_chunk($array_chunkdata,5); $rev_counter = 2; function for_chunk($chunk_data){ echo "<td><table>"; foreach($chunk_data as $key => $chunk_value) { echo "<tr><td>"; echo $chunk_value; echo "</td></tr>"; } echo "</table></td>"; } foreach($chunk as $key => $chunk_data) { if($rev_counter%2==0) { for_chunk($chunk_data); } else { $chunk_data = array_reverse($chunk_data); for_chunk($chunk_data); } $rev_counter++; } ?>
</tr>
</table>

[#2] Anonymous [2014-05-20 10:51:27]

Couldn't get the array_chunk_values() working, so ended up with this implementation:

<?php function array_chunk_columns($data, $num_columns) { $n = count($data); $per_column = floor($n / $num_columns); $rest = $n % $num_columns; $columns = array(); $index = 0; for ($i = 0; $i < $num_columns; $i++) { // Add an extra item to each column while the column number is less than the // remainder. $add_rest = ($rest && ($i < $rest)) ? 1 : 0; $number = $per_column + $add_rest; $columns[] = array_slice($data, $index, $number); $index += $number; } return $columns; } ?>

[#3] stratboy [2013-09-16 10:22:56]

Hi, I've made  a function to split an array into chunks based on columns wanted. For example:

<?php $a = array(1,2,3,4,5,6,7,8); ?>

goal (say, for 3 columns):

<?php array(    array(1,2,3),    array(4,5,6),    array(7,8) ); ?>

<?php function get_array_columns($array, $columns){                  $columns_map = array();         for($i=0; $i<$columns; $i++){ $columns_map[] = 0; }//init columns                  //create map         $count = count($array);         $position = 0;         while($count > 0){             $columns_map[$position]++;             $position = ($position < $columns-1) ? ++$position : 0;             $count--;         }         //chunk the array based on map         $chunked = array();         foreach($columns_map as $map){             $chunked[] = array_splice($array,0,$map);         }                  return $chunked;     }//end get_array_columns ?>

[#4] nate at ruggfamily dot com [2010-07-19 21:00:27]

If you just want to grab one chunk from an array, you should use array_slice().

[#5] dead dot screamer at seznam dot cz [2009-01-27 02:28:34]

This function can be used to reverse effect of <?php array_Chunk()?>.
<?php function array_Unchunk($array) {     return call_User_Func_Array('array_Merge',$array); } header('Content-Type: text/plain'); $array=array(     array(             'Black Canyon City',             'Chandler',             'Flagstaff',             'Gilbert',             'Glendale',             'Globe',     ),     array(             'Mesa',             'Miami',             'Phoenix',             'Peoria',             'Prescott',             'Scottsdale',     ),     array(             'Sun City',             'Surprise',             'Tempe',             'Tucson',             'Wickenburg',     ), ); var_Dump(array_Unchunk($array)); ?>

Output:
array(17) {
  [0]=>
  string(17) "Black Canyon City"
  [1]=>
  string(8) "Chandler"
  [2]=>
  string(9) "Flagstaff"
  [3]=>
  string(7) "Gilbert"
  [4]=>
  string(8) "Glendale"
  [5]=>
  string(5) "Globe"
  [6]=>
  string(4) "Mesa"
  [7]=>
  string(5) "Miami"
  [8]=>
  string(7) "Phoenix"
  [9]=>
  string(6) "Peoria"
  [10]=>
  string(8) "Prescott"
  [11]=>
  string(10) "Scottsdale"
  [12]=>
  string(8) "Sun City"
  [13]=>
  string(8) "Surprise"
  [14]=>
  string(5) "Tempe"
  [15]=>
  string(6) "Tucson"
  [16]=>
  string(10) "Wickenburg"
}

[#6] Rasmus Schultz (http://mindplay.dk) [2009-01-23 13:59:13]

Unfortunately, this function only accepts real arrays, not iterable objects... For that, you need this function:

<?php function break_array($array, $page_size) { $arrays = array(); $i = 0; foreach ($array as $index => $item) { if ($i++ % $page_size == 0) { $arrays[] = array(); $current = & $arrays[count($arrays)-1]; } $current[] = $item; } return $arrays; } ?>

[#7] OIS [2008-06-10 05:31:51]

Response to azspot at gmail dot com function partition.

$columns = 3;
$citylist = array('Black Canyon City', 'Chandler', 'Flagstaff', 'Gilbert', 'Glendale', 'Globe', 'Mesa', 'Miami', 'Phoenix', 'Peoria', 'Prescott', 'Scottsdale', 'Sun City', 'Surprise', 'Tempe', 'Tucson', 'Wickenburg');
print_r(array_chunk($citylist, ceil(count($citylist) / $columns)));

Output:
Array
(
    [0] => Array
        (
            [0] => Black Canyon City
            [1] => Chandler
            [2] => Flagstaff
            [3] => Gilbert
            [4] => Glendale
            [5] => Globe
        )

    [1] => Array
        (
            [0] => Mesa
            [1] => Miami
            [2] => Phoenix
            [3] => Peoria
            [4] => Prescott
            [5] => Scottsdale
        )

    [2] => Array
        (
            [0] => Sun City
            [1] => Surprise
            [2] => Tempe
            [3] => Tucson
            [4] => Wickenburg
        )

)

[#8] azspot at gmail dot com [2007-05-08 16:53:07]

Tried to use an example below (#56022) for array_chunk_fixed that would "partition" or divide an array into a desired number of split lists -- a useful procedure for "chunking" up objects or text items into columns, or partitioning any type of data resource. However, there seems to be a flaw with array_chunk_fixed ?? for instance, try it with a nine item list and with four partitions. It results in 3 entries with 3 items, then a blank array.

So, here is the output of my own dabbling on the matter:

<?php function partition( $list, $p ) {     $listlen = count( $list );     $partlen = floor( $listlen / $p );     $partrem = $listlen % $p;     $partition = array();     $mark = 0;     for ($px = 0; $px < $p; $px++) {         $incr = ($px < $partrem) ? $partlen + 1 : $partlen;         $partition[$px] = array_slice( $list, $mark, $incr );         $mark += $incr;     }     return $partition; } $citylist = array( "Black Canyon City", "Chandler", "Flagstaff", "Gilbert", "Glendale", "Globe", "Mesa", "Miami",                    "Phoenix", "Peoria", "Prescott", "Scottsdale", "Sun City", "Surprise", "Tempe", "Tucson", "Wickenburg" ); print_r( partition( $citylist, 3 ) ); ?>

Array
(
    [0] => Array
        (
            [0] => Black Canyon City
            [1] => Chandler
            [2] => Flagstaff
            [3] => Gilbert
            [4] => Glendale
            [5] => Globe
        )

    [1] => Array
        (
            [0] => Mesa
            [1] => Miami
            [2] => Phoenix
            [3] => Peoria
            [4] => Prescott
            [5] => Scottsdale
        )

    [2] => Array
        (
            [0] => Sun City
            [1] => Surprise
            [2] => Tempe
            [3] => Tucson
            [4] => Wickenburg
        )

)

[#9] [2006-03-21 16:19:16]

Here my array_chunk_values( ) with values distributed by lines (columns are balanced as much as possible) :

<?php function array_chunk_vertical($data, $columns) { $n = count($data) ; $per_column = floor($n / $columns) ; $rest = $n % $columns ; // The map $per_columns = array( ) ; for ( $i = 0 ; $i < $columns ; $i++ ) { $per_columns[$i] = $per_column + ($i < $rest ? 1 : 0) ; } $tabular = array( ) ; foreach ( $per_columns as $rows ) { for ( $i = 0 ; $i < $rows ; $i++ ) { $tabular[$i][ ] = array_shift($data) ; } } return $tabular ; } header('Content-Type: text/plain') ; $data = array_chunk_vertical(range(1, 31), 7) ; foreach ( $data as $row ) { foreach ( $row as $value ) { printf('[%2s]', $value) ; } echo "\r\n" ; } ?>

[#10] magick dit crow ot gmail dit com [2005-10-16 09:50:20]

Mistake key did not do what I thought. A patch.

function array_bucket($array,$bucket_size)// bucket filter
{
if (!is_array($array)) return false;
$buckets=array_chunk($array,$bucket_size);// chop up array into bucket size units
$I=0;
foreach ($buckets as $bucket)
{
$new_array[$I++]=array_sum($bucket)/count($bucket);
}
return $new_array;// return new array
}

[#11] magick dit crow ot gmail dit com [2005-10-15 10:58:24]

This function takes each few elements of an array and averages them together. It then places the averages in a new array. It is used to smooth out data. For example lets say you have a years worth of hit data to a site and you want to graph it by the week. Then use a bucket of 7 and graph the functions output.

function array_bucket($array, $bucket_size)  // bucket filter
{
if (!is_array($array)) return false; // no empty arrays
$buckets=array_chunk($array,$bucket_size);  // chop up array into bucket size units
foreach ($buckets as $bucket) $new_array[key($buckets])=array_sum($bucket)/count($bucket);
return $new_array;  // return new smooth array
}

[#12] webmaster at cafe-clope dot net [2005-08-20 16:27:29]

based on the same syntax, useful about making columns :

<?php function array_chunk_fixed($input, $num, $preserve_keys = FALSE) {     $count = count($input) ;     if($count)         $input = array_chunk($input, ceil($count/$num), $preserve_keys) ;     $input = array_pad($input, $num, array()) ;     return $input ; } $array = array(1, 2, 3, 4, 5) ; print_r(array_chunk($array, 2)) ; print_r(array_chunk_fixed($array, 2)) ; ?>

---- array_chunk : fixed number of sub-items ----
Array(
    [0] => Array(
            [0] => 1
            [1] => 2
        )
    [1] => Array(
            [0] => 3
            [1] => 4
        )

    [2] => Array(
            [0] => 5
        )
)

---- array_chunk : fixed number of columns ----
Array(
    [0] => Array(
            [0] => 1
            [1] => 2
            [2] => 3
        )
    [1] => Array(
            [0] => 4
            [1] => 5
        )
)

[#13] phpm at nreynolds dot me dot uk [2004-12-17 04:21:36]

array_chunk() is helpful when constructing tables with a known number of columns but an unknown number of values, such as a calendar month. Example:

<?php $values = range(1, 31); $rows = array_chunk($values, 7); print "<table>\n"; foreach ($rows as $row) {     print "<tr>\n";     foreach ($row as $value) {         print "<td>" . $value . "</td>\n";     }     print "</tr>\n"; } print "</table>\n"; ?>

Outputs:

1 2 3 4 5 6 7
8 9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31

The other direction is possible too, with the aid of a function included at the bottom of this note. Changing this line:
  $rows = array_chunk($values, 7);

To this:
  $rows = array_chunk_vertical($values, 7);

Produces a vertical calendar with seven columns:

1 6  11 16 21 26 31
2 7  12 17 22 27
3 8  13 18 23 28
4 9  14 19 24 29
5 10 15 20 25 30

You can also specify that $size refers to the number of rows, not columns:
  $rows = array_chunk_vertical($values, 7, false, false);

Producing this:

1 8  15 22 29
2 9  16 23 30
3 10 17 24 31
4 11 18 25
5 12 19 26
6 13 20 27
7 14 21 28

The function:

<?php function array_chunk_vertical($input, $size, $preserve_keys = false, $size_is_horizontal = true) {     $chunks = array();          if ($size_is_horizontal) {         $chunk_count = ceil(count($input) / $size);     } else {         $chunk_count = $size;     }          for ($chunk_index = 0; $chunk_index < $chunk_count; $chunk_index++) {         $chunks[] = array();     }     $chunk_index = 0;     foreach ($input as $key => $value)     {         if ($preserve_keys) {             $chunks[$chunk_index][$key] = $value;         } else {             $chunks[$chunk_index][] = $value;         }                  if (++$chunk_index == $chunk_count) {             $chunk_index = 0;         }     }          return $chunks; } ?>

[#14] mick at vandermostvanspijk dot nl [2004-04-07 03:02:33]

[Editors note: This function was based on a previous function by gphemsley at nospam users dot sourceforge.net]

For those of you that need array_chunk() for PHP < 4.2.0, this function should do the trick:

<?php if (!function_exists('array_chunk')) { function array_chunk( $input, $size, $preserve_keys = false) { @reset( $input ); $i = $j = 0; while( @list( $key, $value ) = @each( $input ) ) { if( !( isset( $chunks[$i] ) ) ) { $chunks[$i] = array(); } if( count( $chunks[$i] ) < $size ) { if( $preserve_keys ) { $chunks[$i][$key] = $value; $j++; } else { $chunks[$i][] = $value; } } else { $i++; if( $preserve_keys ) { $chunks[$i][$key] = $value; $j++; } else { $j = 0; $chunks[$i][$j] = $value; } } } return $chunks; } } ?>