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
我刚刚创建了一个ArrayHelper类，它可以使数值索引变得非常容易。
class ArrayHelper
{
/*
Inserts a value at the given position or throws an exception if
the position is out of range.
This function will push the current values up in index. ex. if
you insert at index 1 then the previous value at index 1 will
be pushed to index 2 and so on.
$pos: The position where the inserted value should be placed.
Starts at 0.
*/
public static function insertValueAtPos(array &$array, $pos, $value) {
$maxIndex = count($array)-1;
if ($pos === 0) {
array_unshift($array, $value);
} elseif (($pos > 0) && ($pos <= $maxIndex)) {
$firstHalf = array_slice($array, 0, $pos);
$secondHalf = array_slice($array, $pos);
$array = array_merge($firstHalf, array($value), $secondHalf);
} else {
throw new IndexOutOfBoundsException();
}
}
}
例子:
$array = array('a', 'b', 'c', 'd', 'e');
$insertValue = 'insert';
\ArrayHelper::insertValueAtPos($array, 3, $insertValue);
开始$数组:
Array (
[0] => a
[1] => b
[2] => c
[3] => d
[4] => e
)
结果:
Array (
[0] => a
[1] => b
[2] => c
[3] => insert
[4] => d
[5] => e
)
其他回答
如果你只是想在数组的某个位置插入一个项(基于@clausvdb的答案):
function array_insert($arr, $insert, $position) {
$i = 0;
$ret = array();
foreach ($arr as $key => $value) {
if ($i == $position) {
$ret[] = $insert;
}
$ret[] = $value;
$i++;
}
return $ret;
}
Array_slice()可以用来提取数组的部分，联合数组操作符(+)可以重新组合这些部分。
$res = array_slice($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);
给:
Array
(
[zero] => 0
[one] => 1
[two] => 2
[my_key] => my_value
[three] => 3
)
我刚刚创建了一个ArrayHelper类，它可以使数值索引变得非常容易。
class ArrayHelper
{
/*
Inserts a value at the given position or throws an exception if
the position is out of range.
This function will push the current values up in index. ex. if
you insert at index 1 then the previous value at index 1 will
be pushed to index 2 and so on.
$pos: The position where the inserted value should be placed.
Starts at 0.
*/
public static function insertValueAtPos(array &$array, $pos, $value) {
$maxIndex = count($array)-1;
if ($pos === 0) {
array_unshift($array, $value);
} elseif (($pos > 0) && ($pos <= $maxIndex)) {
$firstHalf = array_slice($array, 0, $pos);
$secondHalf = array_slice($array, $pos);
$array = array_merge($firstHalf, array($value), $secondHalf);
} else {
throw new IndexOutOfBoundsException();
}
}
}
例子:
$array = array('a', 'b', 'c', 'd', 'e');
$insertValue = 'insert';
\ArrayHelper::insertValueAtPos($array, 3, $insertValue);
开始$数组:
Array (
[0] => a
[1] => b
[2] => c
[3] => d
[4] => e
)
结果:
Array (
[0] => a
[1] => b
[2] => c
[3] => insert
[4] => d
[5] => e
)
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
)
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)
);
}
