假设我们有两个数组:
$array_1 = array(
'0' => 'zero',
'1' => 'one',
'2' => 'two',
'3' => 'three',
);
$array_2 = array(
'zero' => '0',
'one' => '1',
'two' => '2',
'three' => '3',
);
现在,我想在每个数组的第三个元素后插入数组('sample_key' => 'sample_value')。我该怎么做呢?
这是一个老问题,但我在2014年发表了一篇评论,经常回到这个问题。我想我应该留下一个完整的答案。这不是最短的解决方案,但很容易理解。
在关联数组中插入一个新值,在有编号的位置,保留键并保持顺序。
$columns = array(
'id' => 'ID',
'name' => 'Name',
'email' => 'Email',
'count' => 'Number of posts'
);
$columns = array_merge(
array_slice( $columns, 0, 3, true ), // The first 3 items from the old array
array( 'subscribed' => 'Subscribed' ), // New value to add after the 3rd item
array_slice( $columns, 3, null, true ) // Other items after the 3rd
);
print_r( $columns );
/*
Array (
[id] => ID
[name] => Name
[email] => Email
[subscribed] => Subscribed
[count] => Number of posts
)
*/
如果你不知道你想在位置3插入它,但你知道你想在后面插入它的键,在看到这个问题后,我想出了这个小函数。
/**
* Inserts any number of scalars or arrays at the point
* in the haystack immediately after the search key ($needle) was found,
* or at the end if the needle is not found or not supplied.
* Modifies $haystack in place.
* @param array &$haystack the associative array to search. This will be modified by the function
* @param string $needle the key to search for
* @param mixed $stuff one or more arrays or scalars to be inserted into $haystack
* @return int the index at which $needle was found
*/
function array_insert_after(&$haystack, $needle = '', $stuff){
if (! is_array($haystack) ) return $haystack;
$new_array = array();
for ($i = 2; $i < func_num_args(); ++$i){
$arg = func_get_arg($i);
if (is_array($arg)) $new_array = array_merge($new_array, $arg);
else $new_array[] = $arg;
}
$i = 0;
foreach($haystack as $key => $value){
++$i;
if ($key == $needle) break;
}
$haystack = array_merge(array_slice($haystack, 0, $i, true), $new_array, array_slice($haystack, $i, null, true));
return $i;
}
这里是一个代码板小提琴看到它的行动:http://codepad.org/5WlKFKfz
注意:array_splice()会比array_merge(array_slice())更有效,但这样你插入的数组的键就会丢失。叹息。
Array_slice()可以用来提取数组的部分,联合数组操作符(+)可以重新组合这些部分。
$res = array_slice($array, 0, 3, true) +
array("my_key" => "my_value") +
array_slice($array, 3, count($array)-3, true);
这个例子:
$array = array(
'zero' => '0',
'one' => '1',
'two' => '2',
'three' => '3',
);
$res = array_slice($array, 0, 3, true) +
array("my_key" => "my_value") +
array_slice($array, 3, count($array) - 1, true) ;
print_r($res);
给:
Array
(
[zero] => 0
[one] => 1
[two] => 2
[my_key] => my_value
[three] => 3
)
非常简单的2个字符串回答你的问题:
$array_1 = array(
'0' => 'zero',
'1' => 'one',
'2' => 'two',
'3' => 'three',
);
首先,你用array_splice向第三个元素插入任何东西,然后给这个元素赋值:
array_splice($array_1, 3, 0 , true);
$array_1[3] = array('sample_key' => 'sample_value');