array_splice保留键

Question

我遇到了使用保留键拼接数组的情况,所以我做了以下功能.
我达到了用数组包装每个项目的解决方案,但似乎有一些内存效率低下的语句.
你有什么想法吗？
谢谢.

---

array_splice_pk

这保留了密钥,不同于array_splice.

概述:

• &$input- >与array_splice一个相同.
• $key - >目标键.
• $use_key_as_offset- >使用$key参数作为数字偏移量.
• $length- >与array_splice一个相同.
• $replacement- >与array_splice一个相同.但您也可以为每个值提供密钥.

码:

function array_splice_pk(&$input, $key, $use_key_as_offset = false, $length = 0, $replacement = null) {
    if (!is_array($input) || !is_scalar($key)) {
        return array();
    }
    if ($replacement !== null) {
        $replacement = array($replacement);
        if (!is_array($replacement[0])) {
            $replacement = array($replacement);
        }
    }
    $wrapper = array();
    foreach ($input as $k => $v) {
        $wrapper[] = array($k => $v);
    }
    $del_key = null;
    foreach ($wrapper as $k => $v) {
        if ($use_key_as_offset) {
            if ($k === (int)$key) {
                $del_key = $k;
                break;
            }
        } else {
            if (key($v) == $key) {
                $del_key = $k;
                break;
            }
        }
    }
    if ($del_key === null) {
        return array();
    }
    if ($replacement === null) {
        $wrapper_ret = array_splice($wrapper, $del_key, $length);
    } else {
        $wrapper_ret = array_splice($wrapper, $del_key, $length , $replacement);
    }
    $ret = $input = array();
    foreach ($wrapper_ret as $wrap) {
        list($k, $v) = each($wrap);
        $ret[$k] = $v;
    }
    foreach ($wrapper as $wrap) {
        list($k ,$v) = each($wrap);
        $input[$k] = $v;
    }
    return $ret;
}

样品:

$arr1 = $arr2 = array(
    'one'   => 'test',
    'two'   => 'test',
    'three' => 'test',
    'four'  => 'test',
);
$ret1 = array_splice_pk($arr1, 'three', false, 1, array('fizz' => '!!!'));
$ret2 = array_splice_pk($arr2, 2      , true , 1, array('fizz' => '!!!'));

var_dump('Result1', $arr1, $ret1, 'Result2', $arr2, $ret2);

结果:

string(7) "Result1"
array(4) {
  ["one"]=>
  string(4) "test"
  ["two"]=>
  string(4) "test"
  ["fizz"]=>
  string(3) "!!!"
  ["four"]=>
  string(4) "test"
}
array(1) {
  ["three"]=>
  string(4) "test"
}
string(7) "Result2"
array(4) {
  ["one"]=>
  string(4) "test"
  ["two"]=>
  string(4) "test"
  ["fizz"]=>
  string(3) "!!!"
  ["four"]=>
  string(4) "test"
}
array(1) {
  ["three"]=>
  string(4) "test"
}

Answer 1

我在array_slice的手册中找到了这个.

<?php
function array_splice_assoc(&$input, $offset, $length, $replacement = array()) {
    $replacement = (array) $replacement;
    $key_indices = array_flip(array_keys($input));
    if (isset($input[$offset]) && is_string($offset)) {
            $offset = $key_indices[$offset];
    }
    if (isset($input[$length]) && is_string($length)) {
            $length = $key_indices[$length] - $offset;
    }

    $input = array_slice($input, 0, $offset, TRUE)
            + $replacement
            + array_slice($input, $offset + $length, NULL, TRUE); 
}

 $fruit = array(
    'orange' => 'orange',
    'lemon' => 'yellow',
    'lime' => 'green',
    'grape' => 'purple',
    'cherry' => 'red',
 );

  // Replace lemon and lime with apple
  array_splice_assoc($fruit, 'lemon', 'grape', array('apple' => 'red'));

  // Replace cherry with strawberry
  array_splice_assoc($fruit, 'cherry', 1, array('strawberry' => 'red'));
  ?>

在保留密钥的同时,它似乎更节省空间和时间.

Answer 2

我将在 2022 年用我的 PHP 8 知识发布自我回答。
它正确接受负长度/偏移量和字符串偏移量。

function array_splice_assoc(array &$input, int|string $key, ?int $length = null, $replacement = [], bool $use_int_key_as_offset = true): array
{
    // Normalize key/offset
    $offset = match (true) {
        is_string($key) || !$use_int_key_as_offset => array_flip(array_keys($input))[$key] ?? throw new OutOfBoundsException(),
        $key < 0 => count($input) + $key,
        default => $key,
    };

    // Normalize length
    $length = match (true) {
        $length === null => count($input) - $offset,
        $length < 0 => count($input) + $length - $offset,
        default => $length,
    };

    // Manipulate each part
    $before = array_slice($input, 0, $offset, true);
    $removed = array_slice($input, $offset, $length, true);
    $after = array_slice($input, $offset + $length, null, true);

    // Merge parts, allowing the latter overrides the former
    $input = array_replace($before, (array)$replacement, $after);

    return $removed;
}

例子：

$array = ['a' => 'A', 'b' => 'B', 3 => 'C', 4 => 'D'];

$original = $array;
$removed = array_splice_assoc($original, 1, 1, [5 => 'E']);
echo json_encode(compact('original', 'removed')) . PHP_EOL;
/*
{"original":{"a":"A","5":"E","3":"C","4":"D"},"removed":{"b":"B"}}
*/

$original = $array;
$removed = array_splice_assoc($original, 2, replacement: [5 => 'E']);
echo json_encode(compact('original', 'removed')) . PHP_EOL;
/*
{"original":{"a":"A","b":"B","5":"E"},"removed":{"3":"C","4":"D"}}
*/

$original = $array;
$removed = array_splice_assoc($original, -3, 1, [5 => 'E']);
echo json_encode(compact('original', 'removed')) . PHP_EOL;
/*
{"original":{"a":"A","5":"E","3":"C","4":"D"},"removed":{"b":"B"}}
*/

$original = $array;
$removed = array_splice_assoc($original, -3, -1, [5 => 'E']);
echo json_encode(compact('original', 'removed')) . PHP_EOL;
/*
{"original":{"a":"A","5":"E","4":"D"},"removed":{"b":"B","3":"C"}}
*/

$original = $array;
$removed = array_splice_assoc($original, 'b', 2, [5 => 'E']);
echo json_encode(compact('original', 'removed')) . PHP_EOL;
/*
{"original":{"a":"A","5":"E","4":"D"},"removed":{"b":"B","3":"C"}}
*/

$original = $array;
$removed = array_splice_assoc($original, 3, 1, [5 => 'E']);
echo json_encode(compact('original', 'removed')) . PHP_EOL;
/*
{"original":{"a":"A","b":"B","3":"C","5":"E"},"removed":{"4":"D"}}
*/

$original = $array;
$removed = array_splice_assoc($original, 3, 1, [5 => 'E'], false);
echo json_encode(compact('original', 'removed')) . PHP_EOL;
/*
{"original":{"a":"A","b":"B","5":"E","4":"D"},"removed":{"3":"C"}}
*/