PHP 函数数组默认值？

Question

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Answer 1

函数参数的默认值只能使用标量类型。

您还可以在手册中阅读:http://php.net/manual/en/functions.arguments.php#functions.arguments.default

引自那里:

The default value must be a constant expression, not (for example) a variable, a class member or a function call.

编辑:

但是如果你仍然需要这个值作为数组中的默认值，你可以这样做:

只需使用一个占位符，如果使用默认数组，您可以将其替换为 str_replace()。如果您多次需要默认数组中函数的返回值，这也有好处，您只需要使用相同的占位符，两者都将被替换。

public function create(
    $data = [
        "user-id" => "::PLACEHOLDER1::",
                    //^^^^^^^^^^^^^^^^ See here just use a placeholder
        "level" => '1',
        "ignore-limits" => '0',
    ]){
    $data = str_replace("::PLACEHOLDER1::", Auth::id(), $data);
          //^^^^^^^^^^^ If you didn't passed an argument and the default array with the placeholder is used it get's replaced
    //$data = str_replace("::PLACEHOLDER2::", Auth::id(), $data); <- AS many placeholder as you need; Just make sure they are unique
    //...
}

你可以做的另一个想法是设置一个默认数组，你可以检查它然后像这样分配真正的数组:

public function create($data = []){
    if(count($data) == 0) {
        $data = [
            "user-id" => Auth::id(),
            "level" => '1',
            "ignore-limits" => '0',
        ];    
    }
    //...
}