php5.5新数组函数array

PHP发布了其中增加了一个新的数组函数array_column感觉不错的！但是低版本PHP要使用得自己实现
参考地址

复制代码 代码如下:
if(!function_exists(array_column)){
function array_column($input $columnKey $indexKey=null){
$columnKeyIsNumber = (is_numeric($columnKey)) ? true : false;
$indexKeyIsNull = (is_null($indexKey)) ? true : false;
$indexKeyIsNumber = (is_numeric($indexKey)) ? true : false;
$result = array();
foreach((array)$input as $key=>$row){
if($columnKeyIsNumber){
$tmp = array_slice($row $columnKey );
$tmp = (is_array($tmp) && !empty($tmp)) ? current($tmp) : null;
}else{
$tmp = isset($row[$columnKey]) ? $row[$columnKey] : null;
}
if(!$indexKeyIsNull){
if($indexKeyIsNumber){
$key = array_slice($row $indexKey );
$key = (is_array($key) && !empty($key)) ? current($key) : null;
$key = is_null($key) ? : $key;
}else{
$key = isset($row[$indexKey]) ? $row[$indexKey] : ;
}
}
$result[$key] = $tmp;
}
return $result;
}
}

// 使用例子
$records = array(
array(
id =>
first_name => John
last_name => Doe
)
array(
id =>
first_name => Sally
last_name => Smith
)
array(
id =>
first_name => Jane
last_name => Jones
)
array(
id =>
first_name => Peter
last_name => Doe
)
);
$firstNames = array_column($records first_name);
print_r($firstNames);
/*
Array
(
[] => John
[] => Sally
[] => Jane
[] => Peter
)
*/

$records = array(
array( John Doe)
array( Sally Smith)
array( Jane Jones)
);
$lastNames = array_column($records );
print_r($lastNames);
/*
Array
(
[] => Doe
[] => Smith
[] => Jones
)
*/

$mismatchedColumns = array(
array(
a => foo
b => bar
e => baz
)
array(
a => qux
c => quux
d => corge
)
array(
a => grault
b => garply
e => waldo
)
);
$foo = array_column($mismatchedColumns a b);
print_r($foo);
/*
Array
(
[bar] => foo
[] => qux
[garply] => grault
)
*/

array_column 用于获取二维数组中的元素(PHP >= )

复制代码 代码如下:
<?php
// Array representing a possible record set returned from a database
$records = array(
array(
id =>
first_name => John
last_name => Doe
)
array(
id =>
first_name => Sally
last_name => Smith
)
array(
id =>
first_name => Jane
last_name => Jones
)
array(
id =>
first_name => Peter
last_name => Doe
)
);

$first_names = array_column($records first_name);
print_r($first_names);
?>
Array
(
[] => John
[] => Sally
[] => Jane
[] => Peter
)<?php
// Using the $records array from Example #
$last_names = array_column($records last_name id);
print_r($last_names);
?>
Array
(
[] => Doe
[] => Smith
[] => Jones
[] => Doe
)