在静态类中使用另一个文件中的外部数组

问题描述：

I'm currently working on a project where I have to work with huge arrays. With huge, I mean 1k elements or more. Since these are a lot of arrays and i sometimes mess things up, I decided to create a class with static functions so i can call the functions which would make the entire project easier to read. This is what I currently have:

ArrayAccess.class.php:

require "dep/arrays/elements.php";
class ArrayAccess {

    public static function get_value_from_element($element) {
        return $elements[$element];
    }
}

elements.php:

<?php
$elements = array(
    "sam" => 6, ... and so on ...

I simply want to be able to use ArrayAccess::get_value_from_element($element) in my project. It is so much easier to read than all these indexes everywhere. However, the array is defined in the elements.php file - I can't use that in the class.

So how can I access the array in my class? Please note, I cannot copy it into the class, the file would be larger than 400k lines, this is not an option.

我正在开发一个项目，我必须使用大型数组。巨大的，我的意思是1k或更多元素。由于这些是很多数组而且我有时搞砸了，所以我决定用静态函数创建一个类，这样我就可以调用函数来使整个项目更容易阅读。这就是我目前所拥有的： p>

ArrayAccess.class.php： p>

  require“dep / arrays / elements.php”; \  nclass ArrayAccess {
 
公共静态函数get_value_from_element（$ element）{
 return $ elements [$ element]; 
} 
} 
  code>  pre> 
 
 元素 .php： p> 
 
 
 ＆lt;？php 
 $ elements = array（
“sam”=＆gt; 6，...等等...... 
   pre> 
 
 我只是希望能够在我的项目中使用 ArrayAccess :: get_value_from_element（$ element） code>。它比所有阅读更容易阅读 这些索引无处不在。但是，数组是在 elements.php  code>文件中定义的 - 我不能在类中使用它。 p> 
 
 
那么如何访问 我班上的数组？请注意，我不能将它复制到类中，文件大于400k行，这不是一个选项。 p> 
  div>

答

You can return a value from an include (or require in this case) and store that to a static property the first time the function is called.

elements.php:

<?php
return array("sam" => 6, ...);

DataAccess.php:

class DataAccess {

    private static $elements = array();

    public static function get_value_from_element($element) {
        if(self::$elements === array()) {
            self::$elements = require "elements.php";
        }
        return self::$elements[$element];
    }
}

You should also avoid naming your class ArrayAccess, since it already exists in PHP.

答

In elements.php

<?php
return array( // use return so you can retrieve these into a variable
      "sam" => 6, ... and so on ...

Then in the class

<?php
class ArrayAccess {
    public static $elements = null; // set up a static var to avoid load this big array multiple times
    public static function get_value_from_element($element) {
        if(self::$elements === null) { // check if null to load it from the file
            self::$elements = require('elements.php');
        }
        return self::$elements[$element]; // there you go
    }
}

If you don't want do the if statement in the getter every time, you should probably find some where else to load the file into the static variable before using the getter.

答

An alternative is to declare $elements as global in your class:

require "dep/arrays/elements.php";
class ArrayAccess {

    public static function get_value_from_element($element) {
        global $elements;
        return $elements[$element];
    }
}

在静态类中使用另一个文件中的外部数组

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