阵列中的重复键 [英] Duplicate keys in Array

问题描述

在类型转换期间防止重复键的最佳方法是什么?

What is the best way to prevent duplicate key during type casting ?

示例:

//Credits @bwoebi
$obj = (object)array(1,2,3);
$obj->{1} = "Duplicate key 1";
$obj->{2} = "Duplicate key 2";
$obj->{3} = "Duplicate key 3";
$array = (array)$obj ;
print_r($array);

输出

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [1] => Duplicate key 1
    [2] => Duplicate key 2
    [3] => Duplicate key 3
)

现在我知道一些聪明的人会说它，因为一个key是string而另一个int使用var_dump

Now i know some smart people would say its because one key is string and the other int use var_dump

var_dump($array);

输出

array (size=6)
  0 => int 1
  1 => int 2
  2 => int 3
  '1' => string 'Duplicate key 1' (length=15)
  '2' => string 'Duplicate key 2' (length=15)
  '3' => string 'Duplicate key 3' (length=15)

但是主要问题是甚至没有办法获得密钥

But the main issue is there is no way to even get the key

echo $array['1'] ,PHP_EOL;     //Expected Duplicate key 1
echo $array[1] ,PHP_EOL;

输出

2
2

有没有解决此问题的方法而不必循环?显然，除非@PeeHaa埽再给我啤酒，否则我永远不会犯这个错误，但我认为任何答案都应有助于受过教育的PHP开发人员.

Is there any workaround to this issue without having to loop ? Obviously i would never make this mistake unless @PeeHaa埽 gives be beer again, but I think any answer should help educated PHP developers.

注意. -可以使用array_values，sort或任何更改键位置的php函数轻松解决此问题

Note. - This can easly be resolved with array_values , sort or any php function that changes key position

示例

sort($array);
print_r($array);

输出

Array
(
    [0] => Duplicate key 1
    [1] => Duplicate key 2
    [2] => Duplicate key 3
    [3] => 1
    [4] => 2
    [5] => 3
)

推荐答案

我认为， only 解决方案(即唯一不是丑陋的东西)就是停止使用匿名对象并为此定义一个类.不必太复杂:

The way I see this, the only solution (i.e. the only thing that isn't an ugly hack) is to stop using anonymous objects and define a class for this purpose. It doesn't need to be complicated:

class SimpleArrayObject
{
    public function __construct($array = null)
    {
        foreach ((array) $array as $key => $value) {
            $this->{$key} = $value; // implicitly calls __set()
        }
    }

    public function __set($key, $value)
    {
        $this->{(string) $key} = $value;
    }
}

由于使用__set()并将所有内容都定义为动态公共属性，因此对于json_encode()，foreach，转换以及您希望从stdClass进行的所有其他操作，它仍然可以很好地发挥作用.但是，这会强制使用属性名称的字符串类型，这意味着不再有重叠的松散类型.

Because of the use of __set() and defining everything as dynamic public properties, this will still play nice with json_encode(), foreach, casting and all the other things you would expect from a stdClass. However this enforces a string type for property names, meaning that the overlapping loose types is no longer possible.

您还可以定义一个辅助函数，以使广播"语法非常清楚:

You can also define a helper function to allow you to make the "casting" syntax quite clear what's going on:

function object($value)
{
    if (is_object($value)) {
        return $value;
    }

    if (!is_array($value)) { // mimic the behaviour of a regular cast
        $value = array('scalar' => $value);
    }

    return new SimpleArrayObject($value);
}

看看会发生什么:

$obj = object(array(1,2,3));
$obj->{1} = "Duplicate key 1";
$obj->{2} = "Duplicate key 2";
$obj->{3} = "Duplicate key 3";
$array = (array)$obj ;
print_r($array);

输出:

Array
(
    [0] => 1
    [1] => Duplicate key 1
    [2] => Duplicate key 2
    [3] => Duplicate key 3
)

这篇关于阵列中的重复键的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！