php PHP中的“as”运算符
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'as' operator in PHP
提问by Randomblue
In PHP, what does the operator 'as' do? For example,
在 PHP 中，运算符“as”有什么作用？例如，
foreach ( $this->Example as $Example )
Thanks.
谢谢。
回答by Shoe
Let's take an example:
让我们举个例子：
foreach ($array as $value) {}
This means
这意味着
foreach element (of
$array) defined as$value...
foreach 元素 (of
$array) 定义为$value...
In other words this means that the elements of the array will be retrieved inside the loop as$value.
Notice that you can specify also this syntax:
换句话说，这意味着将在循环内检索数组的元素as$value。请注意，您还可以指定以下语法：
foreach ($array as $key => $value) {}
In both ways the vars $keyand $valuewill exists inside the foreachand will correspond to the 'current' element of the array.
在这两种方式中，vars$key和$valuewill 都存在于foreach数组中，并且将对应于数组的“当前”元素。
回答by Ry-
It's only used with foreachand it defines the variable (or key/value variable pair) that represents the current item in the array.
它仅用于foreach和它定义表示数组中当前项的变量（或键/值变量对）。
回答by Mike Lewis
On each iteration of the foreach loop, $Exampleis assigned to the current element in the loop.
在 foreach 循环的每次迭代中，$Example分配给循环中的当前元素。
回答by Sergej Jevsejev
here is info from http://php.net/manual/en/control-structures.foreach.php
这是来自http://php.net/manual/en/control-structures.foreach.php 的信息
foreach (array_expression as $value)
statement
The first form loops over the array given by array_expression.
第一种形式循环遍历由 array_expression 给出的数组。
On each loop, the value of the current element is assigned to $valueand the internal array pointer is advanced by one (so on the next loop, you'll be looking at the next element).
在每个循环中，当前元素的值被分配给 $value并且内部数组指针前进一个（因此在下一个循环中，您将查看下一个元素）。
回答by cprn
Just to expand on existing answers. There's more than one use of askeyword. Besides the obvious:
只是为了扩展现有的答案。as关键字的用法不止一种。除了显而易见的：
foreach ($dictionary as $key => $value) {}
It's also used to alias imported resources:
它还用于别名导入的资源：
<?php
namespace foo;
use Full\Class\Path as MyAlias;
new MyAlias();
Which is useful, e.g. as a shorthand for AVeryLongClassNameThatRendersYourCodeUnreadableor to substitute an object with your implementation when extending third party code.
这很有用，例如，AVeryLongClassNameThatRendersYourCodeUnreadable在扩展第三方代码时，作为一个对象的简写或用您的实现替换一个对象。
回答by lonesomeday
It's used in a foreachconstruct to iterate through an array. The code in the foreachblock will be run for each element in the array (in this example, $this->Example). Every time it is run, the variable after as(in this example, $Example) will be set to the value of the current element in the array.
它在foreach构造中用于遍历数组。foreach块中的代码将针对数组中的每个元素（在本例中为$this->Example）运行。每次运行时，变量 after as（在本例中为$Example）将设置为数组中当前元素的值。
回答by sv_in
Takes each entries in the array ie, $this->Example and puts it in $Example
获取数组中的每个条目，即 $this->Example 并将其放入 $Example
more details in http://php.net/manual/en/control-structures.foreach.php
更多细节在http://php.net/manual/en/control-structures.foreach.php
