"PHP Error: Call to a member function getKey() on string" from diff() method on Laravel Collection

Question

以下是转储的集合：

//$collOne
Illuminate\Database\Eloquent\Collection {#3386
  #items: array:6 [
    4807 => "{"color_id":7,"size_id":4,"pack_id":null}"
    4808 => "{"color_id":7,"size_id":2,"pack_id":null}"
    4809 => "{"color_id":7,"size_id":6,"pack_id":null}"
    4840 => "{"color_id":44,"size_id":4,"pack_id":null}"
    4841 => "{"color_id":44,"size_id":6,"pack_id":null}"
    4842 => "{"color_id":44,"size_id":2,"pack_id":null}"
  ]
}
//$collTwo
Illuminate\Database\Eloquent\Collection {#3403
  #items: array:5 [
    430 => "{"color_id":7,"size_id":4,"pack_id":null}"
    431 => "{"color_id":7,"size_id":2,"pack_id":null}"
    433 => "{"color_id":44,"size_id":4,"pack_id":null}"
    434 => "{"color_id":44,"size_id":6,"pack_id":null}"
    435 => "{"color_id":44,"size_id":2,"pack_id":null}"
  ]
}

这是错误：

{
    "message": "Call to a member function getKey() on string",
    "exception": "Symfony\Component\Debug\Exception\FatalThrowableError",
    "file": "[obfuscated]/vendor/laravel/framework/src/Illuminate/Database/Eloquent/Collection.php",
    "line": 281,
    "trace": [
        {
            "file": "[obfuscated].php",
            "line": 174,
            "function": "diff",
            "class": "Illuminate\Database\Eloquent\Collection",
            "type": "->"
        },

这是上述错误中引用的第 174 行：

$diff = $collOne->diff($collTwo);

文档看起来很简单：

The diff method compares the collection against another collection or a plain PHP array based on its values. This method will return the values in the original collection that are not present in the given collection:

我是不是漏掉了什么明显的东西？

Answer 1

我怀疑当您调用 mapWithKeys 时您没有 return Model 实例。这就是导致错误的原因。 Illuminate\Database\Eloquent\Collection 必须是 Eloquent 个模型的集合，但在本例中不是。

解决方法是在基础集合中调用 diff，而不是像这样在 Eloquent 集合中调用：

$diff = $collOne->toBase()->diff($collTwo->toBase());

或者，当您调用 mapWithKeys 时，像这样在基础集合上调用它：

$eloqCollection->toBase()->mapWithKeys(function($...) {...}) 两个系列。然后您可以使用相同的代码：$diff = $collOne->diff($collTwo); 来计算差异，因为现在 $collOne 和 $collTwo 都是 Illuminate\Support\Collection

的实例

"PHP Error: Call to a member function getKey() on string" from diff() method on Laravel Collection

"PHP Error: Call to a member function getKey() on string" from diff() method on Laravel Collection

php

laravel

laravel-5

laravel-collection

laravel-5.7