php5.5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：https://wiki.php.net/rfc/array_column
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, 1);
$tmp = (is_array($tmp) && !empty($tmp)) ? current($tmp) : null;
}else{
$tmp = isset($row[$columnkey]) ? $row[$columnkey] : null;
}
if(!$indexkeyisnull){
if($indexkeyisnumber){
$key = array_slice($row, $indexkey, 1);
$key = (is_array($key) && !empty($key)) ? current($key) : null;
$key = is_null($key) ? 0 : $key;
}else{
$key = isset($row[$indexkey]) ? $row[$indexkey] : 0;
}
}
$result[$key] = $tmp;
}
return $result;
}
}
// 使用例子
$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'
)
);
$firstnames = array_column($records, 'first_name');
print_r($firstnames);
/*
array
(
[0] => john
[1] => sally
[2] => jane
[3] => peter
)
*/
$records = array(
array(1, 'john', 'doe'),
array(2, 'sally', 'smith'),
array(3, 'jane', 'jones')
);
$lastnames = array_column($records, 2);
print_r($lastnames);
/*
array
(
[0] => doe
[1] => smith
[2] => 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
[0] => qux
[garply] => grault
)
*/
array_column 用于获取二维数组中的元素(php 5 >= 5.5.0)
复制代码 代码如下:
<?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);
?>
array
(
[0] => john
[1] => sally
[2] => jane
[3] => peter
)<?php
// using the $records array from example #1
$last_names = array_column($records, 'last_name', 'id');
print_r($last_names);
?>
array
(
[2135] => doe
[3245] => smith
[5342] => jones
[5623] => doe
)
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