if array_column does not exist the below solution will work.
if(!function_exists("array_column"))
{
function array_column($array,$column_name)
{
return array_map(function($element) use($column_name){return $element[$column_name];}, $array);
}
}
array_column
(PHP 5 >= 5.5.0, PHP 7)
array_column — 返回数组中指定的一列
说明
array_column()
返回input数组中键值为column_key的列，
如果指定了可选参数index_key，那么input数组中的这一列的值将作为返回数组中对应值的键。
参数
-
input -
需要取出数组列的多维数组（或结果集）
-
column_key -
需要返回值的列，它可以是索引数组的列索引，或者是关联数组的列的键。 也可以是
NULL，此时将返回整个数组（配合index_key参数来重置数组键的时候，非常管用） -
index_key -
作为返回数组的索引/键的列，它可以是该列的整数索引，或者字符串键值。
返回值
从多维数组中返回单列数组
范例
Example #1 从结果集中取出first names列
<?php
// Array representing a possible record set returned from a database
$records = array(
array(
'id' => 2135,
'first_name' => 'John',
'last_name' => 'Doe',
),
array(
'id' => 3245,
'first_name' => 'Sally',
'last_name' => 'Smith',
),
array(
'id' => 5342,
'first_name' => 'Jane',
'last_name' => 'Jones',
),
array(
'id' => 5623,
'first_name' => 'Peter',
'last_name' => 'Doe',
)
);
$first_names = array_column($records, 'first_name');
print_r($first_names);
?>
以上例程会输出：
Array
(
[0] => John
[1] => Sally
[2] => Jane
[3] => Peter
)
Example #2 从结果集中总取出last names列，用相应的id作为键值
<?php
// Using the $records array from Example #1
$last_names = array_column($records, 'last_name', 'id');
print_r($last_names);
?>
以上例程会输出：
Array
(
[2135] => Doe
[3245] => Smith
[5342] => Jones
[5623] => Doe
)
add a note
User Contributed Notes 13 notes
mohanrajnr at gmail dot com ¶
10 months ago
WARrior ¶
2 years ago
You can also use array_map fucntion if you haven't array_column().
example:
$a = array(
array(
'id' => 2135,
'first_name' => 'John',
'last_name' => 'Doe',
),
array(
'id' => 3245,
'first_name' => 'Sally',
'last_name' => 'Smith',
)
);
array_column($a, 'last_name');
becomes
array_map(function($element){return $element['last_name'];}, $a);
till at etill dot net ¶
9 months ago
Some remarks not included in the official documentation.
1) array_column does not support 1D arrays, in which case an empty array is returned.
2) The $column_key is zero-based.
3) If $column_key extends the valid index range an empty array is returned.
Anonymous ¶
1 month ago
I added a little more functionality to the more popular answers here to support the $index_key parameter for PHP < 5.5
<?php
// for php < 5.5
if (!function_exists('array_column')) {
function array_column($input, $column_key, $index_key = null) {
$arr = array_map(function($d) use ($column_key, $index_key) {
if (!isset($d[$column_key])) {
return null;
}
if ($index_key !== null) {
return array($d[$index_key] => $d[$column_key]);
}
return $d[$column_key];
}, $input);
if ($index_key !== null) {
$tmp = array();
foreach ($arr as $ar) {
$tmp[key($ar)] = current($ar);
}
$arr = $tmp;
}
return $arr;
}
}
?>
Nolan chou ¶
24 days ago
if (!function_exists('array_column'))
{
function array_column($input, $column_key=null, $index_key=null)
{
$result = array();
$i = 0;
foreach ($input as $v)
{
$k = $index_key === null || !isset($v[$index_key]) ? $i++ : $v[$index_key];
$result[$k] = $column_key === null ? $v : (isset($v[$column_key]) ? $v[$column_key] : null);
}
return $result;
}
}
kaspar dot wilbuer at web dot de ¶
1 month ago
If you need to extract more than one column from an array, you can use array_intersect_key on each element, like so:
function array_column_multi(array $input, array $column_keys) {
$result = array();
$column_keys = array_flip($column_keys);
foreach($input as $key => $el) {
$result[$key] = array_intersect_key($el, $column_keys);
}
return $result;
}
antonfedonjuk at gmail dot com ¶
8 months ago
My version is closer to the original than http://github.com/ramsey/array_column
<?php
/**
* Provides functionality for array_column() to projects using PHP earlier than
* version 5.5.
* @copyright (c) 2015 WinterSilence (http://github.com/WinterSilence)
* @license MIT
*/
if (!function_exists('array_column')) {
/**
* Returns an array of values representing a single column from the input
* array.
* @param array $array A multi-dimensional array from which to pull a
* column of values.
* @param mixed $columnKey The column of values to return. This value may
* be the integer key of the column you wish to retrieve, or it may be
* the string key name for an associative array. It may also be NULL to
* return complete arrays (useful together with index_key to reindex
* the array).
* @param mixed $indexKey The column to use as the index/keys for the
* returned array. This value may be the integer key of the column, or
* it may be the string key name.
* @return array
*/
function array_column(array $array, $columnKey, $indexKey = null)
{
$result = array();
foreach ($array as $subArray) {
if (!is_array($subArray)) {
continue;
} elseif (is_null($indexKey) && array_key_exists($columnKey, $subArray)) {
$result[] = $subArray[$columnKey];
} elseif (array_key_exists($indexKey, $subArray)) {
if (is_null($columnKey)) {
$result[$subArray[$indexKey]] = $subArray;
} elseif (array_key_exists($columnKey, $subArray)) {
$result[$subArray[$indexKey]] = $subArray[$columnKey];
}
}
}
return $result;
}
}
?>
kiler129 @ nowhere ¶
1 year ago
Please note this function accepts 2D-arrays ONLY, and silently returns empty array when non-array argument is provided.
Code:
class testObject {
public $a = 123;
}
$testArray = [new testObject(), new testObject(), new testObject()];
$result = array_column($testArray, 'a')); //array(0) { }
hypxm at qq dot com ¶
1 year ago
a simple solution:
function arrayColumn(array $array, $column_key, $index_key=null){
if(function_exists('array_column ')){
return array_column($array, $column_key, $index_key);
}
$result = [];
foreach($array as $arr){
if(!is_array($arr)) continue;
if(is_null($column_key)){
$value = $arr;
}else{
$value = $arr[$column_key];
}
if(!is_null($index_key)){
$key = $arr[$index_key];
$result[$key] = $value;
}else{
$result[] = $value;
}
}
return $result;
}
coviex ¶
1 year ago
Value for existing key in the resulting array is rewritten with new value if it exists in another source sub-array.
marianbucur17 at yahoo dot com ¶
10 months ago
If array_column is not available you can use the following function, which also has the $index_key parameter:
if (!function_exists('array_column')) {
function array_column($array, $column_key, $index_key = null)
{
return array_reduce($array, function ($result, $item) use ($column_key, $index_key)
{
if (null === $index_key) {
$result[] = $item[$column_key];
} else {
$result[$item[$index_key]] = $item[$column_key];
}
return $result;
}, []);
}
}
robbieaverill[at]gmail.com ¶
11 months ago
Another option for older PHP versions (pre 5.5.0) is to use array_walk():
<?php
$array = array(
array('some' => 'var', 'foo' => 'bar'),
array('some' => 'var', 'foo' => 'bar'),
array('some' => 'var', 'foo' => 'bar')
);
array_walk($array, function(&$value, $key, $return) {
$value = $value[$return];
}, 'foo');
print_r($array);
// Array
// (
// [0] => bar
// [1] => bar
// [2] => bar
// )
?>
myles at smyl dot es ¶
1 year ago
This didn't work for me recursively and needed to come up with a solution.
Here's my solution to the function:
if ( ! function_exists( 'array_column_recursive' ) ) {
/**
* Returns the values recursively from columns of the input array, identified by
* the $columnKey.
*
* Optionally, you may provide an $indexKey to index the values in the returned
* array by the values from the $indexKey column in the input array.
*
* @param array $input A multi-dimensional array (record set) from which to pull
* a column of values.
* @param mixed $columnKey The column of values to return. This value may be the
* integer key of the column you wish to retrieve, or it
* may be the string key name for an associative array.
* @param mixed $indexKey (Optional.) The column to use as the index/keys for
* the returned array. This value may be the integer key
* of the column, or it may be the string key name.
*
* @return array
*/
function array_column_recursive( $input = NULL, $columnKey = NULL, $indexKey = NULL ) {
// Using func_get_args() in order to check for proper number of
// parameters and trigger errors exactly as the built-in array_column()
// does in PHP 5.5.
$argc = func_num_args();
$params = func_get_args();
if ( $argc < 2 ) {
trigger_error( "array_column_recursive() expects at least 2 parameters, {$argc} given", E_USER_WARNING );
return NULL;
}
if ( ! is_array( $params[ 0 ] ) ) {
// Because we call back to this function, check if call was made by self to
// prevent debug/error output for recursiveness :)
$callers = debug_backtrace();
if ( $callers[ 1 ][ 'function' ] != 'array_column_recursive' ){
trigger_error( 'array_column_recursive() expects parameter 1 to be array, ' . gettype( $params[ 0 ] ) . ' given', E_USER_WARNING );
}
return NULL;
}
if ( ! is_int( $params[ 1 ] )
&& ! is_float( $params[ 1 ] )
&& ! is_string( $params[ 1 ] )
&& $params[ 1 ] !== NULL
&& ! ( is_object( $params[ 1 ] ) && method_exists( $params[ 1 ], '__toString' ) )
) {
trigger_error( 'array_column_recursive(): The column key should be either a string or an integer', E_USER_WARNING );
return FALSE;
}
if ( isset( $params[ 2 ] )
&& ! is_int( $params[ 2 ] )
&& ! is_float( $params[ 2 ] )
&& ! is_string( $params[ 2 ] )
&& ! ( is_object( $params[ 2 ] ) && method_exists( $params[ 2 ], '__toString' ) )
) {
trigger_error( 'array_column_recursive(): The index key should be either a string or an integer', E_USER_WARNING );
return FALSE;
}
$paramsInput = $params[ 0 ];
$paramsColumnKey = ( $params[ 1 ] !== NULL ) ? (string) $params[ 1 ] : NULL;
$paramsIndexKey = NULL;
if ( isset( $params[ 2 ] ) ) {
if ( is_float( $params[ 2 ] ) || is_int( $params[ 2 ] ) ) {
$paramsIndexKey = (int) $params[ 2 ];
} else {
$paramsIndexKey = (string) $params[ 2 ];
}
}
$resultArray = array();
foreach ( $paramsInput as $row ) {
$key = $value = NULL;
$keySet = $valueSet = FALSE;
if ( $paramsIndexKey !== NULL && array_key_exists( $paramsIndexKey, $row ) ) {
$keySet = TRUE;
$key = (string) $row[ $paramsIndexKey ];
}
if ( $paramsColumnKey === NULL ) {
$valueSet = TRUE;
$value = $row;
} elseif ( is_array( $row ) && array_key_exists( $paramsColumnKey, $row ) ) {
$valueSet = TRUE;
$value = $row[ $paramsColumnKey ];
}
$possibleValue = array_column_recursive( $row, $paramsColumnKey, $paramsIndexKey );
if ( $possibleValue ) {
$resultArray = array_merge( $possibleValue, $resultArray );
}
if ( $valueSet ) {
if ( $keySet ) {
$resultArray[ $key ] = $value;
} else {
$resultArray[ ] = $value;
}
}
}
return $resultArray;
}
}
