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

要将元素插入到具有字符串键的数组中,您可以这样做:

/* insert an element after given array key
 * $src = array()  array to work with
 * $ins = array() to insert in key=>array format
 * $pos = key that $ins will be inserted after
 */ 
function array_insert_string_keys($src,$ins,$pos) {

    $counter=1;
    foreach($src as $key=>$s){
        if($key==$pos){
            break;
        }
        $counter++;
    } 

    $array_head = array_slice($src,0,$counter);
    $array_tail = array_slice($src,$counter);

    $src = array_merge($array_head, $ins);
    $src = array_merge($src, $array_tail);

    return($src); 
} 

你可能会觉得这更直观一些。它只需要调用array_splice一个函数:

$original = array( 'a', 'b', 'c', 'd', 'e' );
$inserted = array( 'x' ); // not necessarily an array, see manual quote
 
array_splice( $original, 3, 0, $inserted ); // splice in at position 3
// $original is now a b c x d e

如果replacement只是一个元素,则没有必要在它周围加上array(),除非该元素本身是数组、对象或NULL。

RETURN VALUE:需要注意的是,函数不返回所需的替换。$original通过引用传递,并在适当的位置进行编辑。请参阅参数列表中带有&的表达式array &$array。

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. 

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

如何使用array_splice()保存数组键

@jay的答案。Lee是正确的,不幸的是,它不能保存数组的键,正如评论中指出的那样:

$original = array( 
    'a' => 'A', 
    'b' => 'B', 
    'c' => 'C', 
    // insert here
    'd' => 'D', 
    'e' => 'E');

$inserted = array( 'x' => 'X' ); 

array_splice( $original, 3, 0, $inserted );
print_r($original);

/* Output
Array
(
    [a] => A
    [b] => B
    [c] => C
    [0] => X  <= the lost key 
    [d] => D
    [e] => E
) */

我发现保存数组键的最简单的方法是使用array_splice()函数,并使用+ /联合操作符将数组添加在一起(也在另一个答案的评论中提到):

$original = array( 
    'a' => 'A', 
    'b' => 'B', 
    'c' => 'C', 
    // insert here
    'd' => 'D', 
    'e' => 'E');

$inserted = array( 'x' => 'X' ); 

// Insert before postion 'd'
$before = array_splice( $original, 0, 3 ); // $original contains the left over

// Merge together
$result = $before + $inserted + $original;
print_r($result);

/* Output
Array
(
    [a] => A
    [b] => B
    [c] => C
    [x] => X
    [d] => D
    [e] => E
) */

注意:使用数组联合操作符仅在处理非数字键时是安全的


谢谢你的更正@mickmackusa