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
这是PHP 7.1中的另一个解决方案
/**
* @param array $input Input array to add items to
* @param array $items Items to insert (as an array)
* @param int $position Position to inject items from (starts from 0)
*
* @return array
*/
function arrayInject( array $input, array $items, int $position ): array
{
if (0 >= $position) {
return array_merge($items, $input);
}
if ($position >= count($input)) {
return array_merge($input, $items);
}
return array_merge(
array_slice($input, 0, $position, true),
$items,
array_slice($input, $position, null, true)
);
}
其他回答
这里有一个你可以使用的简单函数。只要插进去就行了。
这是按索引插入，而不是按值插入。
您可以选择传递该数组，或者使用已经声明的数组。
较新的、较短的版本:
function insert($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( $array3, 'undefined assoc key', 'new key', 'new value', true, true) );
结果:
Array
(
[0] => zero
[1] => one
[2] => two
[3] => three
[three+] => three+ value
[4] => four
)
Array
(
[zero] => # 0
[one] => # 1
[two] => # 2
[three] => # 3
[three+] => three+ value
[four] => # 4
)
Array
(
[0] => zero
[1] => one
[before-64] => before-64 value
[64] => 64
[3] => three
[4] => four
)
Array
(
[0] => zero
[1] => one
[64] => 64
[3] => three
[4] => four
[new key] => new value
)
不像Artefacto的答案那么具体，但基于他使用array_slice()的建议，我写了下一个函数:
function arrayInsert($target, $byKey, $byOffset, $valuesToInsert, $afterKey) {
if (isset($byKey)) {
if (is_numeric($byKey)) $byKey = (int)floor($byKey);
$offset = 0;
foreach ($target as $key => $value) {
if ($key === $byKey) break;
$offset++;
}
if ($afterKey) $offset++;
} else {
$offset = $byOffset;
}
$targetLength = count($target);
$targetA = array_slice($target, 0, $offset, true);
$targetB = array_slice($target, $offset, $targetLength, true);
return array_merge($targetA, $valuesToInsert, $targetB);
}
特点:
插入一个或múltiple值 插入键值对 在键前/键后插入，或按偏移量插入
使用例子:
$target = [
'banana' => 12,
'potatoe' => 6,
'watermelon' => 8,
'apple' => 7,
2 => 21,
'pear' => 6
];
// Values must be nested in an array
$insertValues = [
'orange' => 0,
'lemon' => 3,
3
];
// By key
// Third parameter is not applicable
// Insert after 2 (before 'pear')
var_dump(arrayInsert($target, 2, null, $valuesToInsert, true));
// Insert before 'watermelon'
var_dump(arrayInsert($target, 'watermelon', null, $valuesToInsert, false));
// By offset
// Second and last parameter are not applicable
// Insert in position 2 (zero based i.e. before 'watermelon')
var_dump(arrayInsert($target, null, 2, $valuesToInsert, null));
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。
这是一个老问题，但我在2014年发表了一篇评论，经常回到这个问题。我想我应该留下一个完整的答案。这不是最短的解决方案，但很容易理解。
在关联数组中插入一个新值，在有编号的位置，保留键并保持顺序。
$columns = array(
'id' => 'ID',
'name' => 'Name',
'email' => 'Email',
'count' => 'Number of posts'
);
$columns = array_merge(
array_slice( $columns, 0, 3, true ), // The first 3 items from the old array
array( 'subscribed' => 'Subscribed' ), // New value to add after the 3rd item
array_slice( $columns, 3, null, true ) // Other items after the 3rd
);
print_r( $columns );
/*
Array (
[id] => ID
[name] => Name
[email] => Email
[subscribed] => Subscribed
[count] => Number of posts
)
*/
