如何将一个新项目插入到数组的任何位置,例如在数组的中间?
当前回答
如果你想保留初始数组的键,并添加一个有键的数组,那么使用下面的函数:
function insertArrayAtPosition( $array, $insert, $position ) {
/*
$array : The initial array i want to modify
$insert : the new array i want to add, eg array('key' => 'value') or array('value')
$position : the position where the new array will be inserted into. Please mind that arrays start at 0
*/
return array_slice($array, 0, $position, TRUE) + $insert + array_slice($array, $position, NULL, TRUE);
}
电话的例子:
$array = insertArrayAtPosition($array, array('key' => 'Value'), 3);
其他回答
$result_array = array();
$array = array("Tim","John","Mark");
$new_element = "Bill";
$position = 1;
for ($i=0; $i<count($array); $i++)
{
if ($i==$position)
{
$result_array[] = $new_element;
}
$result_array[] = $array[$i];
}
print_r($result_array);
// Result will Array([0] => "Tim",[1] => "Bill", [2] => "John",[1] => "Mark")
这可以通过array_splice完成,但是,当插入数组或使用字符串键时,array_splice会失败。我写了一个函数来处理所有情况:
function array_insert(&$arr, $index, $val)
{
if (is_string($index))
$index = array_search($index, array_keys($arr));
if (is_array($val))
array_splice($arr, $index, 0, [$index => $val]);
else
array_splice($arr, $index, 0, $val);
}
可以在整数和字符串位置进行插入的函数:
/**
* @param array $array
* @param int|string $position
* @param mixed $insert
*/
function array_insert(&$array, $position, $insert)
{
if (is_int($position)) {
array_splice($array, $position, 0, $insert);
} else {
$pos = array_search($position, array_keys($array));
$array = array_merge(
array_slice($array, 0, $pos),
$insert,
array_slice($array, $pos)
);
}
}
整数的用法:
$arr = ["one", "two", "three"];
array_insert(
$arr,
1,
"one-half"
);
// ->
array (
0 => 'one',
1 => 'one-half',
2 => 'two',
3 => 'three',
)
字符串的用法:
$arr = [
"name" => [
"type" => "string",
"maxlength" => "30",
],
"email" => [
"type" => "email",
"maxlength" => "150",
],
];
array_insert(
$arr,
"email",
[
"phone" => [
"type" => "string",
"format" => "phone",
],
]
);
// ->
array (
'name' =>
array (
'type' => 'string',
'maxlength' => '30',
),
'phone' =>
array (
'type' => 'string',
'format' => 'phone',
),
'email' =>
array (
'type' => 'email',
'maxlength' => '150',
),
)
这也是一个有效的解决方案:
function array_insert(&$array,$element,$position=null) {
if (count($array) == 0) {
$array[] = $element;
}
elseif (is_numeric($position) && $position < 0) {
if((count($array)+position) < 0) {
$array = array_insert($array,$element,0);
}
else {
$array[count($array)+$position] = $element;
}
}
elseif (is_numeric($position) && isset($array[$position])) {
$part1 = array_slice($array,0,$position,true);
$part2 = array_slice($array,$position,null,true);
$array = array_merge($part1,array($position=>$element),$part2);
foreach($array as $key=>$item) {
if (is_null($item)) {
unset($array[$key]);
}
}
}
elseif (is_null($position)) {
$array[] = $element;
}
elseif (!isset($array[$position])) {
$array[$position] = $element;
}
$array = array_merge($array);
return $array;
}
获奖者: http://binarykitten.com/php/52-php-insert-element-and-shift.html
如果你有正则数组,没有什么特别的,这就可以了。记住,使用array_splice()插入元素实际上意味着在开始索引之前插入。移动元素时要小心,因为向上移动意味着$targetIndex -1,向下移动意味着$targetIndex + 1。
class someArrayClass
{
private const KEEP_EXISTING_ELEMENTS = 0;
public function insertAfter(array $array, int $startIndex, $newElements)
{
return $this->insertBefore($array, $startIndex + 1, $newElements);
}
public function insertBefore(array $array, int $startIndex, $newElements)
{
return array_splice($array, $startIndex, self::KEEP_EXISTING_ELEMENTS, $newElements);
}
}