是否有来自阵列（字典）通过键获取默认值的更好的方式PHP？ [英] Is there a better PHP way for getting default value by key from array (dictionary)?

问题描述

在的Python 的人可以做的：

foo = {}
assert foo.get('bar', 'baz') == 'baz'

在 PHP 的人可以去一个三元opeartor为：

In PHP one can go for a trinary opeartor as in:

$foo = array();
assert( (isset($foo['bar'])) ? $foo['bar'] : 'baz' == 'baz');

我要寻找一个高尔夫版本。我能做到这一点在PHP短/更好？

I am looking for a golf version. Can I do it shorter/better in PHP?

推荐答案

我刚刚想出了这个小助手功能：

I just came up with this little helper function:

function get(&$var, $default=null) {
    return isset($var) ? $var : $default;
}

这不仅工作字典，而是对所有类型的变量：

Not only does this work for dictionaries, but for all kind of variables:

$test = array('foo'=>'bar');
get($test['foo'],'nope'); // bar
get($test['baz'],'nope'); // nope
get($test['spam']['eggs'],'nope'); // nope
get($undefined,'nope'); // nope

传递一个previously未定义的变量元参不引起的通知错误。相反，通过 $ VAR 引用将定义它，它设置为空。的默认值也随之如果传递的变量是空返回。还要注意隐式生成的数组中的垃圾邮件/鸡蛋例如：

Passing a previously undefined variable per reference doesn't cause a NOTICE error. Instead, passing $var by reference will define it and set it to null. The default value will also be returned if the passed variable is null. Also note the implicitly generated array in the spam/eggs example:

json_encode($test); // {"foo":"bar","baz":null,"spam":{"eggs":null}}
$undefined===null; // true (got defined by passing it to get)
isset($undefined) // false
get($undefined,'nope'); // nope

请注意，即使 $ VAR 通过引用传递，结果的get（$ VAR）将 $ VAR的副本，而不是引用。我希望这有助于！

Note that even though $var is passed by reference, the result of get($var) will be a copy of $var, not a reference. I hope this helps!

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