如何创建一个小PHP脚本，根据部分/价格计算一些项目？

我想用PHP编写一个脚本，这将为我做一些数学计算

它应完成以下任务：

示例

假设你有一家网上果汁店。 你想

将几种果汁保存到数据库中（想想：橙汁、柠檬汁、苹果汁）

您还需要保存这些果汁的分量和价格（例如100ml/2,50美元）

您想要混合/组合不同的果汁，并获得毫升/美元的总量

如果我们加起来：

橙汁：100毫升/2,50美元|我要50毫升=1,25美元

苹果汁：100毫升/1,50美元|我要10毫升=0,15美元

总果汁混合：60ml=1,40美元。

到目前为止还不错。 我编写了以下代码：

<?php
  function devide() {
  $portion = 100;         //variable for ml    
  $price = 2.50;          //variable for price
  $portionNew = 50;       //value for new portion put into total mix
    if($portionNew > 0) {
      echo ($price / 100 * $portionNew);  //calculates price of new portion
    } 
  }
      echo "Total Juice" . (" = ");  
      echo devide() . (" USD") ;
?>

此代码仅计算从一种果汁中取出的部分的价格。 如果你从100毫升果汁中提取30毫升，它将与价格相呼应

以下是我的问题：

如何使此脚本不仅响应新的价格，而且响应新的部分（

$portionNew

）

关于我希望最终脚本执行的操作，函数是否是正确的开始？还是应该考虑对象或数组呢？

我应该如何继续使用这个脚本，以便它能够添加多个（

$portionNews/$price

）来告诉我最终的价格和我的果汁总混合比例

只需在

devide

函数中添加类似

echo'部分：'.$portionNew

。（我相信您可能想称之为

除法

？）

您可以创建一个

Juice

类，但我认为在这种情况下这样做太过分了。我可能会坚持使用一个数组来存储果汁及其价格，并使用一个函数来混合多种果汁

你可以创建一个混合果汁的函数。您可以指定一个变量，该变量包含当前价格和混合中的部分、要添加的果汁的类型和数量，它将返回一个表示混合中果汁的新价格和数量的值

如果要将果汁存储在阵列中，它可以如下所示：

// In this case, we have an array that maps the juice type to a price (in cents
// per 100 ml).
$juices = array(
    'orange' => 250,
    'apple' => 150
);

// If you decide you need to store more information about a juice, you can change
// this array to map a juice type to another associative array that contains the
// price and your additional information.
// Beware: if you use this, you have to change the mixJuices function to access
// a juice's "price" value:
//     $pricePerLiter = $juices[$juiceType]['price'] * 10;
$juices = array(
    'orange' => array(
        'price' => 250,
        'color' => 'orange'
    ),
    'apple' => array(
        'price' => 150,
        'color' => 'yellow'
    )
);

// The function needs to know what's currently in the mix, which is why it's
// taking the $currentMix as a parameter. Also, it needs to know about all the
// available juices, which is why it's taking the $juices as another parameter.
// A mix is represented by an associative array that contains the current amount
// of juice in the mix (identified by "portion") and the current price
// (identified by "price"). Note that you need to pass the $juices array I
// defined earlier, so it can access the different types of juices and their 
// prices.
function mixJuices($currentMix, $juices, $juiceType, $juicePortion)
{
    $pricePerLiter = $juices[$juiceType] * 10;
    $price = $pricePerLiter * $juicePortion / 1000;
    $currentMix['portion'] = $currentMix['portion'] + $juicePortion;
    $currentMix['price'] = $currentMix['price'] + $price;
    return $currentMix;
}

// At the beginning, there's no juice at all, so it doesn't cost anything (yet)
$mix = array('portion' => 0, 'price' => 0);

// Let's mix some juice in
$mix = mixJuices($mix, $juices, 'apple', 500);
$mix = mixJuices($mix, $juices, 'orange', 250);

// Print the amount of juice and the price
// The price is divided by 100 so we can display it in dollars instead of cents
echo sprintf('%d milliliters of this juice mix will cost %.2f USD.',
    $mix['portion'], $mix['price'] / 100);

请注意，我是用美分而不是美元来设定价格的。通过这样做，我可以避免在计算价格时使用浮动以及与之相关的所有问题（请参阅）

混合果汁的功能可能如下所示：

// In this case, we have an array that maps the juice type to a price (in cents
// per 100 ml).
$juices = array(
    'orange' => 250,
    'apple' => 150
);

// If you decide you need to store more information about a juice, you can change
// this array to map a juice type to another associative array that contains the
// price and your additional information.
// Beware: if you use this, you have to change the mixJuices function to access
// a juice's "price" value:
//     $pricePerLiter = $juices[$juiceType]['price'] * 10;
$juices = array(
    'orange' => array(
        'price' => 250,
        'color' => 'orange'
    ),
    'apple' => array(
        'price' => 150,
        'color' => 'yellow'
    )
);

// The function needs to know what's currently in the mix, which is why it's
// taking the $currentMix as a parameter. Also, it needs to know about all the
// available juices, which is why it's taking the $juices as another parameter.
// A mix is represented by an associative array that contains the current amount
// of juice in the mix (identified by "portion") and the current price
// (identified by "price"). Note that you need to pass the $juices array I
// defined earlier, so it can access the different types of juices and their 
// prices.
function mixJuices($currentMix, $juices, $juiceType, $juicePortion)
{
    $pricePerLiter = $juices[$juiceType] * 10;
    $price = $pricePerLiter * $juicePortion / 1000;
    $currentMix['portion'] = $currentMix['portion'] + $juicePortion;
    $currentMix['price'] = $currentMix['price'] + $price;
    return $currentMix;
}

// At the beginning, there's no juice at all, so it doesn't cost anything (yet)
$mix = array('portion' => 0, 'price' => 0);

// Let's mix some juice in
$mix = mixJuices($mix, $juices, 'apple', 500);
$mix = mixJuices($mix, $juices, 'orange', 250);

// Print the amount of juice and the price
// The price is divided by 100 so we can display it in dollars instead of cents
echo sprintf('%d milliliters of this juice mix will cost %.2f USD.',
    $mix['portion'], $mix['price'] / 100);

此函数也可以编写为使用全局

$mix

变量。如果这样做，就不需要将$currentMix传递给函数。但是，您也将失去同时创建多个混音的能力（因为对修改后的

mixJuices

函数的所有调用都将修改相同的全局混音）

您可以使用我在上面定义的函数，如下所示：

// In this case, we have an array that maps the juice type to a price (in cents
// per 100 ml).
$juices = array(
    'orange' => 250,
    'apple' => 150
);

// If you decide you need to store more information about a juice, you can change
// this array to map a juice type to another associative array that contains the
// price and your additional information.
// Beware: if you use this, you have to change the mixJuices function to access
// a juice's "price" value:
//     $pricePerLiter = $juices[$juiceType]['price'] * 10;
$juices = array(
    'orange' => array(
        'price' => 250,
        'color' => 'orange'
    ),
    'apple' => array(
        'price' => 150,
        'color' => 'yellow'
    )
);

// The function needs to know what's currently in the mix, which is why it's
// taking the $currentMix as a parameter. Also, it needs to know about all the
// available juices, which is why it's taking the $juices as another parameter.
// A mix is represented by an associative array that contains the current amount
// of juice in the mix (identified by "portion") and the current price
// (identified by "price"). Note that you need to pass the $juices array I
// defined earlier, so it can access the different types of juices and their 
// prices.
function mixJuices($currentMix, $juices, $juiceType, $juicePortion)
{
    $pricePerLiter = $juices[$juiceType] * 10;
    $price = $pricePerLiter * $juicePortion / 1000;
    $currentMix['portion'] = $currentMix['portion'] + $juicePortion;
    $currentMix['price'] = $currentMix['price'] + $price;
    return $currentMix;
}

// At the beginning, there's no juice at all, so it doesn't cost anything (yet)
$mix = array('portion' => 0, 'price' => 0);

// Let's mix some juice in
$mix = mixJuices($mix, $juices, 'apple', 500);
$mix = mixJuices($mix, $juices, 'orange', 250);

// Print the amount of juice and the price
// The price is divided by 100 so we can display it in dollars instead of cents
echo sprintf('%d milliliters of this juice mix will cost %.2f USD.',
    $mix['portion'], $mix['price'] / 100);

---

这种方法可以让你做各种有趣的事情

假设您有两位客户想要订购果汁混合物。通过创建两个不同的

$mix

阵列，您可以轻松混合同一类型的多种果汁：

// Process customer 1's order
$mixCustomer1 = array('portion' => 0, 'price' => 0);
$mixCustomer1 = mixJuices($mixCustomer1, $juices, 'apple', 250);
$mixCustomer1 = mixJuices($mixCustomer1, $juices, 'orange', 250);
echo sprintf('%d milliliters of this juice mix will cost %.2f USD.',
    $mixCustomer1['portion'], $mixCustomer1['price'] / 100);
// 500 milliliters of this juice mix will cost 10.00 USD.

// Process customer 2's order
$mixCustomer2 = array('portion' => 0, 'price' => 0);
$mixCustomer2 = mixJuices($mixCustomer2, $juices, 'apple', 150);
$mixCustomer2 = mixJuices($mixCustomer2, $juices, 'orange', 350);
echo sprintf('%d milliliters of this juice mix will cost %.2f USD.',
    $mixCustomer2['portion'], $mixCustomer2['price'] / 100);
// 500 milliliters of this juice mix will cost 11.00 USD.

现在让我们假设客户2有某种代金券，可以让他享受果汁20%的折扣：

// Apply the discount
$discountedJuices = array_map(function($price) { return (1 - 0.2) * $price; }, $juices);

// Process customer 2's order
$mixCustomer2 = array('portion' => 0, 'price' => 0);
$mixCustomer2 = mixJuices($mixCustomer2, $discountedJuices, 'apple', 150);
$mixCustomer2 = mixJuices($mixCustomer2, $discountedJuices, 'orange', 350);
echo sprintf('%d milliliters of this juice mix will cost %.2f USD.',
    $mixCustomer2['portion'], $mixCustomer2['price'] / 100);
// 500 milliliters of this juice mix will cost 8.80 USD.

---

对于美元，你想用

而不是

，

作为小数点，即

0.15美元

伙计，我都不知道该怎么感谢你！你一定花了不少功夫才把这一切写下来。太好了，非常感谢。顺便说一句：至于拼写错误，比如（devide/divide），我不是母语人士，所以有时会感到困惑：）我还有很多问题要问：1）我想在我的果汁中添加更多信息，比如说营养。在第一个数组$juices中，您说过可以通过将juice类型映射到另一个数组来存档它。我在谷歌上搜索了一下，但我似乎没有找到正确的答案。你能在这里进一步解释吗？问题2：$mix是关联数组吗？这对我来说似乎非常复杂，而且我不理解语法…特别是在括号（）中。我读起来像：$var=name（$var，$array，$key，newValue）。但举例来说，为什么偏执论中第二次出现$var？最后但并非最不重要的一点，我要感谢你教我关于“sprint”的知识。我以前不知道…用谷歌搜索并理解它！干得好！THX关于问题1：基本上，不要说

'orange'=>250

（juice=>price），而是说

'orange'=>array（'price'=>250，'color'=>orange'）

（juice=>information array）。我在回答中加了一个例子。关于问题2：是的，

$mix

是一个关联数组

mixJuices

获取包含当前混合信息的数组，并返回包含新混合信息的相同类型的数组。这就是为什么您要传递当前的

$mix

（这样它就知道混合中有什么），并将结果分配给

$mix

（这样您就可以记住添加到混合中的内容）。