Question

假设我有一个具有3个属性的对象：

protected $validMainStatements;
protected $validPrimaryStatements;
protected $validSecondaryStatements;

我得到了以下方法：

public function selectType($stmt) {
    $stmtParts = MainServerInterface::parse($stmt);
    $type = $stmtParts[0] //returns either Main, Primary or Secondary
}

根据type的值，我想使用关联的属性。一个简单的实现是：

public function selectType($stmt) {
    $stmtParts = MainServerInterface::parse($stmt);
    $type = $stmtParts[0] //returns either Main, Primary or Secondary

    if($type === "Main") {
        $usedProp = $this->validMainStatements;
    } elseif($type === "Primary") {
        $usedProp = $this->validPrimaryStatements;
    } elseif($type === "Secondary") {
        $usedProp = $this->validSecondaryStatements;
    }
}

我想我不必提及使用它是丑陋和不舒服的。有没有办法以更简单的方式实现这一点？像（伪代码）的东西：

$usedProp = $"valid".$type."Statements";

Answer 1

<?php
class Foo {
    protected $validMainStatements = 1;
    protected $validPrimaryStatements = 2;
    protected $validSecondaryStatements = 3;

    public function bar() {
        $type = 'Primary';

        return $this->{'valid'.$type.'Statements'};
    }
}

$foo = new Foo;
echo $foo->bar();

请参阅Variable variables - Example #1 Variable property example

- 编辑和顺便说一下：我宁愿这样做：

<?php
class Foo {
    protected $validStatements = [
        'Main' => 1,
        'Primary' => 2,
        'Secondary' => 3
    ];

    public function bar() {
        $type = 'Primary';

        return $this->validStatements[$type];
    }
}

$foo = new Foo;
echo $foo->bar();

Answer 2

Demo

尝试以下

$usedProp = $this->{"valid".$type."Statements"};

<强>测试

<?php

   class test {
         public $validMainStatements = 'hello';
   }

  $instance = new test;

  $type = 'Main'; 
  echo $instance->{"valid".$type."Statements"};

?>

<强>结果

hello

Answer 3

只需使用variable variables。

$variableName = 'valid'.$type.'Statements';
$this->{$variableName};

根据另一个变量的值获取变量

3 个答案: