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，我想要在每个数组的第三个元素之后插入 array('sample_key' => 'sample_value') 。我该如何做？
array_slice()函数可以用来提取数组的部分内容，而联合数组操作符（+）则可将这些部分重新组合。
$res = array_slice($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($res);
数组
(
[zero] => 0
[one] => 1
[two] => 2
[my_key] => my_value
[three] => 3
)
+操作符！请改用array_merge函数！因为如果数组索引是整数（普通数组，不是哈希表），+操作符将无法按预期工作！！！ - Tomasarray_merge对数字键的行为不适用于这个问题。 - Artefactocount($array)-3，您可以直接指定为null以达到相同的效果。另外，正如TMS建议的那样，使用array_merge不需要使用唯一索引。例如：将“new-value”添加到现有数组中：$b = array_merge(array_slice($a, 0, 1, true), array('new-value'), array_slice($a, 1, null, true)); - Radley Sustaire+和array_merge之间似乎存在一些混淆。如果你想要将东西插入到一个数字数组中，你不应该使用+，因为它可能无法满足你的期望。但是你也不应该使用array_merge；对于数字数组，这个问题可以通过array_splice函数来解决。对于关联数组或混合数组，你可能不希望数字键被重新索引，所以使用+是完全适当的。 - meustrus对于您的第一个数组，使用array_splice()函数：
$array_1 = array(
'0' => 'zero',
'1' => 'one',
'2' => 'two',
'3' => 'three',
);
array_splice($array_1, 3, 0, 'more');
print_r($array_1);
输出：
Array(
[0] => zero
[1] => one
[2] => two
[3] => more
[4] => three
)
对于第二个，没有顺序，所以你只需要执行：
$array_2['more'] = '2.5';
print_r($array_2);
并且可以按照您想要的方式对键进行排序。
foreach循环时，数组肯定是有顺序的。这可能重要也可能不重要，这取决于您的最终目标是什么。(我遇到了这个线程，因为在我的情况下，顺序很重要)。非常令人沮丧的是，关联数组没有array_splice()这样的东西。 - cartbeforehorse代码：
function insertValueAtPosition($arr, $insertedArray, $position) {
$i = 0;
$new_array=[];
foreach ($arr as $key => $value) {
if ($i == $position) {
foreach ($insertedArray as $ikey => $ivalue) {
$new_array[$ikey] = $ivalue;
}
}
$new_array[$key] = $value;
$i++;
}
return $new_array;
}
例子：
$array = ["A"=8, "K"=>3];
$insert_array = ["D"= 9];
insertValueAtPosition($array, $insert_array, $position=2);
// result ====> ["A"=>8, "D"=>9, "K"=>3];
可能看起来并不完美，但它能正常工作。
这里有一个简单的函数，可以直接使用。只需要插入即可。
这是按索引插入，而不是按值插入。
您可以选择传递数组，或者使用已经声明的数组。
新的、更短的版本：
function insert($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, $size));
}
}
旧的、较长的版本：
function insert($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
}
使用示例：
//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
)
$list = array(
'Tunisia' => 'Tunis',
'Germany' => 'Berlin',
'Italy' => 'Rom',
'Egypt' => 'Cairo'
);
$afterIndex = 2;
$newVal= array('Palestine' => 'Jerusalem');
$newList = array_merge(array_slice($list,0,$afterIndex+1), $newVal,array_slice($list,$afterIndex+1));
如果您想在某个键后插入元素或数组，最简单的解决方案是：
function array_splice_after_key($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;
}
那么，如果您有以下情况：
$array = [
'one' => 1,
'three' => 3
];
$array_to_insert = ['two' => 2];
并执行：
$result_array = array_splice_after_key($array, 'one', $array_to_insert);
你将获得：
Array (
['one'] => 1
['two'] => 2
['three'] => 3
)
该函数支持：
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( $array3, 'undefined assoc key', 'new key', 'new value', true, true) );
结果：
Array
(
[0] => zero
[1] => one
[2] => two
[3] => three
[three+] => three+ value
[4] => four
)
Array
(
[zero] => # 0
[one] => # 1
[two] => # 2
[three] => # 3
[three+] => three+ value
[four] => # 4
)
Array
(
[0] => zero
[1] => one
[before-64] => before-64 value
[64] => 64
[3] => three
[4] => four
)
Array
(
[0] => zero
[1] => one
[64] => 64
[3] => three
[4] => four
[new key] => new value
)
/**
* Inserts any number of scalars or arrays at the point
* in the haystack immediately after the search key ($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;
}
$toto = array(
'zero' => '0',
'one' => '1',
'two' => '2',
'three' => '3'
);
$ret = array_splice($toto, 3 );
$toto = $toto + array("my_key" => "my_value") + $ret;
print_r($toto);
我最近编写了一个类似于你试图实现的功能的函数，这是一种类似于clasvdb答案的方法。
function magic_insert($index,$value,$input_array ) {
if (isset($input_array[$index])) {
$output_array = array($index=>$value);
foreach($input_array as $k=>$v) {
if ($k<$index) {
$output_array[$k] = $v;
} else {
if (isset($output_array[$k]) ) {
$output_array[$k+1] = $v;
} else {
$output_array[$k] = $v;
}
}
}
} else {
$output_array = $input_array;
$output_array[$index] = $value;
}
ksort($output_array);
return $output_array;
}