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?


当前回答

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。

其他回答

我需要一些可以在键之前,替换,之后插入的东西;如果没有找到目标键,则在数组的开头或结尾添加。默认是在键后插入。

新功能

/**
 * Insert element into an array at a specific key.
 *
 * @param array $input_array
 *   The original array.
 * @param array $insert
 *   The element that is getting inserted; array(key => value).
 * @param string $target_key
 *   The key name.
 * @param int $location
 *   1 is after, 0 is replace, -1 is before.
 *
 * @return array
 *   The new array with the element merged in.
 */
function insert_into_array_at_key(array $input_array, array $insert, $target_key, $location = 1) {
  $output = array();
  $new_value = reset($insert);
  $new_key = key($insert);
  foreach ($input_array as $key => $value) {
    if ($key === $target_key) {
      // Insert before.
      if ($location == -1) {
        $output[$new_key] = $new_value;
        $output[$key] = $value;
      }
      // Replace.
      if ($location == 0) {
        $output[$new_key] = $new_value;
      }
      // After.
      if ($location == 1) {
        $output[$key] = $value;
        $output[$new_key] = $new_value;
      }
    }
    else {
      // Pick next key if there is an number collision.
      if (is_numeric($key)) {
        while (isset($output[$key])) {
          $key++;
        }
      }
      $output[$key] = $value;
    }
  }
  // Add to array if not found.
  if (!isset($output[$new_key])) {
    // Before everything.
    if ($location == -1) {
      $output = $insert + $output;
    }
    // After everything.
    if ($location == 1) {
      $output[$new_key] = $new_value;
    }

  }
  return $output;
}

输入代码

$array_1 = array(
  '0' => 'zero',
  '1' => 'one',
  '2' => 'two',
  '3' => 'three',
);
$array_2 = array(
  'zero'  => '0',
  'one'   => '1',
  'two'   => '2',
  'three' => '3',
);

$array_1 = insert_into_array_at_key($array_1, array('sample_key' => 'sample_value'), 2, 1);
print_r($array_1);
$array_2 = insert_into_array_at_key($array_2, array('sample_key' => 'sample_value'), 'two', 1);
print_r($array_2);

输出

Array
(
    [0] => zero
    [1] => one
    [2] => two
    [sample_key] => sample_value
    [3] => three
)
Array
(
    [zero] => 0
    [one] => 1
    [two] => 2
    [sample_key] => sample_value
    [three] => 3
)

这里有一个你可以使用的简单函数。只要插进去就行了。

这是按索引插入,而不是按值插入。

您可以选择传递该数组,或者使用已经声明的数组。

较新的、较短的版本:

   function insert($array, $index, $val)
   {
       $size = count($array); //because I am going to use this more than one time
       if (!is_int($index) || $index < 0 || $index > $size)
       {
           return -1;
       }
       else
       {
           $temp   = array_slice($array, 0, $index);
           $temp[] = $val;
           return array_merge($temp, array_slice($array, $index, $size));
       }
   }

更老、更长的版本:

  function insert($array, $index, $val) { //function decleration
    $temp = array(); // this temp array will hold the value 
    $size = count($array); //because I am going to use this more than one time
    // Validation -- validate if index value is proper (you can omit this part)       
        if (!is_int($index) || $index < 0 || $index > $size) {
            echo "Error: Wrong index at Insert. Index: " . $index . " Current Size: " . $size;
            echo "<br/>";
            return false;
        }    
    //here is the actual insertion code
    //slice part of the array from 0 to insertion index
    $temp = array_slice($array, 0, $index);//e.g index=5, then slice will result elements [0-4]
    //add the value at the end of the temp array// at the insertion index e.g 5
    array_push($temp, $val);
    //reconnect the remaining part of the array to the current temp
    $temp = array_merge($temp, array_slice($array, $index, $size)); 
    $array = $temp;//swap// no need for this if you pass the array cuz you can simply return $temp, but, if u r using a class array for example, this is useful. 
  
     return $array; // you can return $temp instead if you don't use class array
}

使用的例子:

//1
$result = insert(array(1,2,3,4,5),0, 0);
echo "<pre>";
echo "<br/>";
print_r($result);
echo "</pre>";
//2
$result = insert(array(1,2,3,4,5),2, "a");
echo "<pre>";
print_r($result);
echo "</pre>";
//3
$result = insert(array(1,2,3,4,5) ,4, "b");
echo "<pre>";
print_r($result);
echo "</pre>";
//4
$result = insert(array(1,2,3,4,5),5, 6);
echo "<pre>";
echo "<br/>";
print_r($result);
echo "</pre>";

预期结果:

//1
Array
(
    [0] => 0
    [1] => 1
    [2] => 2
    [3] => 3
    [4] => 4
    [5] => 5
)
//2
Array
(
    [0] => 1
    [1] => 2
    [2] => a
    [3] => 3
    [4] => 4
    [5] => 5
)
//3
Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [4] => b
    [5] => 5
)

//4
Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 4
    [4] => 5
    [5] => 6
)

该函数支持:

数字键和关联键 在建立键之前或之后插入 如果key未建立,则附加到数组末尾


function insert_into_array( $array, $search_key, $insert_key, $insert_value, $insert_after_founded_key = true, $append_if_not_found = false ) {

        $new_array = array();

        foreach( $array as $key => $value ){

            // INSERT BEFORE THE CURRENT KEY? 
            // ONLY IF CURRENT KEY IS THE KEY WE ARE SEARCHING FOR, AND WE WANT TO INSERT BEFORE THAT FOUNDED KEY
            if( $key === $search_key && ! $insert_after_founded_key )
                $new_array[ $insert_key ] = $insert_value;

            // COPY THE CURRENT KEY/VALUE FROM OLD ARRAY TO A NEW ARRAY
            $new_array[ $key ] = $value;

            // INSERT AFTER THE CURRENT KEY? 
            // ONLY IF CURRENT KEY IS THE KEY WE ARE SEARCHING FOR, AND WE WANT TO INSERT AFTER THAT FOUNDED KEY
            if( $key === $search_key && $insert_after_founded_key )
                $new_array[ $insert_key ] = $insert_value;

        }

        // APPEND IF KEY ISNT FOUNDED
        if( $append_if_not_found && count( $array ) == count( $new_array ) )
            $new_array[ $insert_key ] = $insert_value;

        return $new_array;

    }

用法:

    $array1 = array(
        0 => 'zero',
        1 => 'one',
        2 => 'two',
        3 => 'three',
        4 => 'four'
    );

    $array2 = array(
        'zero'  => '# 0',
        'one'   => '# 1',
        'two'   => '# 2',
        'three' => '# 3',
        'four'  => '# 4'
    );

    $array3 = array(
        0 => 'zero',
        1 => 'one',
       64 => '64',
        3 => 'three',
        4 => 'four'
    );


    // INSERT AFTER WITH NUMERIC KEYS
    print_r( insert_into_array( $array1, 3, 'three+', 'three+ value') );

    // INSERT AFTER WITH ASSOC KEYS
    print_r( insert_into_array( $array2, 'three', 'three+', 'three+ value') );

    // INSERT BEFORE
    print_r( insert_into_array( $array3, 64, 'before-64', 'before-64 value', false) );

    // APPEND IF SEARCH KEY ISNT FOUNDED
    print_r( insert_into_array( $array3, 'undefined assoc key', 'new key', 'new value', true, true) );

结果:

Array
(
    [0] => zero
    [1] => one
    [2] => two
    [3] => three
    [three+] => three+ value
    [4] => four
)
Array
(
    [zero] => # 0
    [one] => # 1
    [two] => # 2
    [three] => # 3
    [three+] => three+ value
    [four] => # 4
)
Array
(
    [0] => zero
    [1] => one
    [before-64] => before-64 value
    [64] => 64
    [3] => three
    [4] => four
)
Array
(
    [0] => zero
    [1] => one
    [64] => 64
    [3] => three
    [4] => four
    [new key] => new value
)

你可以在foreach循环中插入元素,因为这个循环工作在原始数组的副本上,但是你必须跟踪插入的行数(在这段代码中我称之为“膨胀”):

$bloat=0;
foreach ($Lines as $n=>$Line)
    {
    if (MustInsertLineHere($Line))
        {
        array_splice($Lines,$n+$bloat,0,"string to insert");
        ++$bloat;
        }
    }

显然,您可以推广这种“膨胀”思想来处理foreach循环期间的任意插入和删除。

最简单的解决方案,如果你想在某个键后插入(一个元素或数组):

function array_splice_after_key($array, $key, $array_to_insert)
{
    $key_pos = array_search($key, array_keys($array));
    if($key_pos !== false){
        $key_pos++;
        $second_array = array_splice($array, $key_pos);
        $array = array_merge($array, $array_to_insert, $second_array);
    }
    return $array;
}

如果你有:

$array = [
    'one' => 1,
    'three' => 3
];
$array_to_insert = ['two' => 2];

和执行:

$result_array = array_splice_after_key($array, 'one', $array_to_insert);

你会有:

Array ( 
    ['one'] => 1 
    ['two'] => 2 
    ['three'] => 3 
)