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(PHP 4 >= 4.2.0, PHP 5)
array_chunk — Splittet ein Array in Teile auf
array_chunk() teilt das Array in Stücke mit size Werten auf. Das letzte Stück kann weniger als size Werte enthalten.
Das Eingabe-Array
Die Größe jedes Arrays
Falls auf TRUE gesetzt, bleiben die Schlüssel erhalten. Der Standard ist FALSE, wodurch jedes Stück neue numerische Indizes erhält.
Gibt ein mehrdimensionales Array zurück, das beginnend mit Null jeweils size Elemente enthält.
Wenn size kleiner als 1 ist, wird E_WARNING geworfen und NULL zurückgegeben.
Beispiel #1 array_chunk()-Beispiel
<?php
$input_array = array('a', 'b', 'c', 'd', 'e');
print_r(array_chunk($input_array, 2));
print_r(array_chunk($input_array, 2, true));
?>
Das oben gezeigte Beispiel erzeugt folgende Ausgabe:
Array
(
[0] => Array
(
[0] => a
[1] => b
)
[1] => Array
(
[0] => c
[1] => d
)
[2] => Array
(
[0] => e
)
)
Array
(
[0] => Array
(
[0] => a
[1] => b
)
[1] => Array
(
[2] => c
[3] => d
)
[2] => Array
(
[4] => e
)
)
If you just want to grab one chunk from an array, you should use array_slice().
This function can be used to reverse effect of <?php array_Chunk()?>.
<?php
function array_Unchunk($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"
}
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;
}
?>
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
)
)
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( $citylist, 3 ) );
?>
Array
(
[0] => Array
(
[0] => Black Canyon City
[1] => Chandler
[2] => Flagstaff
[3] => Gilbert
[4] => Glendale
[5] => Globe
)
[1] => Array
(
[0] => Mesa
[1] => Miami
[2] => Phoenix
[3] => Peoria
[4] => Prescott
[5] => Scottsdale
)
[2] => Array
(
[0] => Sun City
[1] => Surprise
[2] => Tempe
[3] => Tucson
[4] => Wickenburg
)
)
Here my array_chunk_values( ) with values distributed by lines (columns are balanced as much as possible) :
<?php
function array_chunk_vertical($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]', $value) ;
}
echo "\r\n" ;
}
/*
Output :
[ 1][ 6][11][16][20][24][28]
[ 2][ 7][12][17][21][25][29]
[ 3][ 8][13][18][22][26][30]
[ 4][ 9][14][19][23][27][31]
[ 5][10][15]
*/
?>
Mistake key did not do what I thought. A patch.
function array_bucket($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 $new_array;// return new array
}
This function takes each few elements of an array and averages them together. It then places the averages in a new array. It is used to smooth out data. For example lets say you have a years worth of hit data to a site and you want to graph it by the week. Then use a bucket of 7 and graph the functions output.
function array_bucket($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 $new_array; // return new smooth array
}
based on the same syntax, useful about making columns :
<?php
function array_chunk_fixed($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
)
)
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;
}
?>
[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;
}
}
?>
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