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
试试这个:
$colors = array('red', 'blue', 'yellow');
$colors = insertElementToArray($colors, 'green', 2);
function insertElementToArray($arr = array(), $element = null, $index = 0)
{
if ($element == null) {
return $arr;
}
$arrLength = count($arr);
$j = $arrLength - 1;
while ($j >= $index) {
$arr[$j+1] = $arr[$j];
$j--;
}
$arr[$index] = $element;
return $arr;
}
其他回答
function insert(&$arr, $value, $index){
$lengh = count($arr);
if($index<0||$index>$lengh)
return;
for($i=$lengh; $i>$index; $i--){
$arr[$i] = $arr[$i-1];
}
$arr[$index] = $value;
}
通常,使用标量值:
$elements = array('foo', ...);
array_splice($array, $position, $length, $elements);
要在数组中插入一个数组元素,不要忘记将数组包装在数组中(因为它是一个标量值!):
$element = array('key1'=>'value1');
$elements = array($element);
array_splice($array, $position, $length, $elements);
否则,数组的所有键都将逐条添加。
这样你就可以插入数组:
function array_insert(&$array, $value, $index)
{
return $array = array_merge(array_splice($array, max(0, $index - 1)), array($value), $array);
}
如果你有正则数组,没有什么特别的,这就可以了。记住,使用array_splice()插入元素实际上意味着在开始索引之前插入。移动元素时要小心,因为向上移动意味着$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);
}
}
在做了几天之后,这是我能找到的最简单的解决方案。
$indexnumbertoaddat // this is a variable that points to the index # where you
want the new array to be inserted
$arrayToAdd = array(array('key' => $value, 'key' => $value)); //this is the new
array and it's values that you want to add. //the key here is to write it like
array(array('key' =>, since you're adding this array inside another array. This
is the point that a lot of answer left out.
array_splice($originalArray, $indexnumbertoaddatt, 0, $arrayToAdd); //the actual
splice function. You're doing it to $originalArray, at the index # you define,
0 means you're just shifting all other index items down 1, and then you add the
new array.