这个失败:

 define('DEFAULT_ROLES', array('guy', 'development team'));

显然,常量不能保存数组。解决这个问题的最好方法是什么?

define('DEFAULT_ROLES', 'guy|development team');

//...

$default = explode('|', DEFAULT_ROLES);

这似乎是不必要的努力。


当前回答

甚至可以与关联数组工作..例如在课堂上。

class Test {

    const 
        CAN = [
            "can bark", "can meow", "can fly"
        ],
        ANIMALS = [
            self::CAN[0] => "dog",
            self::CAN[1] => "cat",
            self::CAN[2] => "bird"
        ];

    static function noParameter() {
        return self::ANIMALS[self::CAN[0]];
    }

    static function withParameter($which, $animal) {
        return "who {$which}? a {$animal}.";
    }

}

echo Test::noParameter() . "s " . Test::CAN[0] . ".<br>";
echo Test::withParameter(
    array_keys(Test::ANIMALS)[2], Test::ANIMALS["can fly"]
);

// dogs can bark.
// who can fly? a bird.

其他回答

您可以将其作为JSON字符串存储在常量中。从应用程序的角度来看,JSON在其他情况下也很有用。

define ("FRUITS", json_encode(array ("apple", "cherry", "banana")));    
$fruits = json_decode (FRUITS);    
var_dump($fruits);

PHP 5.6+引入了const数组——参见Andrea Faulds的回答。

你也可以序列化你的数组,然后把它放入常量:

# define constant, serialize array
define ("FRUITS", serialize (array ("apple", "cherry", "banana")));

# use it
$my_fruits = unserialize (FRUITS);

甚至可以与关联数组工作..例如在课堂上。

class Test {

    const 
        CAN = [
            "can bark", "can meow", "can fly"
        ],
        ANIMALS = [
            self::CAN[0] => "dog",
            self::CAN[1] => "cat",
            self::CAN[2] => "bird"
        ];

    static function noParameter() {
        return self::ANIMALS[self::CAN[0]];
    }

    static function withParameter($which, $animal) {
        return "who {$which}? a {$animal}.";
    }

}

echo Test::noParameter() . "s " . Test::CAN[0] . ".<br>";
echo Test::withParameter(
    array_keys(Test::ANIMALS)[2], Test::ANIMALS["can fly"]
);

// dogs can bark.
// who can fly? a bird.

你可以将它们存储为类的静态变量:

class Constants {
    public static $array = array('guy', 'development team');
}
# Warning: array can be changed lateron, so this is not a real constant value:
Constants::$array[] = 'newValue';

如果你不喜欢数组可以被其他人更改的想法,getter可能会有所帮助:

class Constants {
    private static $array = array('guy', 'development team');
    public static function getArray() {
        return self::$array;
    }
}
$constantArray = Constants::getArray();

EDIT

从PHP5.4开始,甚至可以在不需要中间变量的情况下访问数组值,即以下工作:

$x = Constants::getArray()['index'];

我知道这是一个有点老的问题,但这是我的解决方案:

<?php
class Constant {

    private $data = [];

    public function define($constant, $value) {
        if (!isset($this->data[$constant])) {
            $this->data[$constant] = $value;
        } else {
            trigger_error("Cannot redefine constant $constant", E_USER_WARNING);
        }
    }

    public function __get($constant) {
        if (isset($this->data[$constant])) {
            return $this->data[$constant];
        } else {
            trigger_error("Use of undefined constant $constant - assumed '$constant'", E_USER_NOTICE);
            return $constant;
        }
    }

    public function __set($constant,$value) {
        $this->define($constant, $value);
    }

}
$const = new Constant;

我定义它是因为我需要在常量中存储对象和数组,所以我也安装了runkit到php,这样我就可以使$const变量超全局。

你可以使用它作为$const->define("my_constant",array("my","values"));或者只是$const->my_constant = array("my","values");

要获取该值,只需调用$const->my_constant;