Question

我试图找出为什么我的代码没有返回与数组值相关联的键。该程序应该将项目的第一个字母与一个数组进行比较，其中字母A-M与＆＃34; 1＆＃34;的关键字相关联。和字母N-Z与＆＃34; 2＆＃34;的关键字相关联。表明他们将位于的过道。我得到的最常见错误是array_search的第二个参数不是数组，但我认为array_combine将两个数组合并为一个新数组，因此（$ aisles，$ letters）应该产生1 =＆gt; A ，1 =＆gt; B等等。我在http://achamlin.gwiddle.co.uk/web182/Project3/HamlinProject3.php上可以找到使用此页面的网页表单。我一直得到相同的输出：＆＃34; Banana位于Aisle。＆＃34;没有列出实际的过道。谢谢你的帮助。

//create function to compare first letter of item to the aisle arrays
function checkAisle($term) {
    $item= "banana";
    $letters = array("A", "B", "C", "D", "E", "F", "G","H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T","U", "V", "W", "X", "Y", "Z");
    $aisles = array("1", "1", "1", "1", "1", "1", "1","1", "1", "1", "1", "1", "1", "2", "2", "2", "2", "2", "2", "2","2", "2", "2", "2", "2", "2");$itemUC = UCfirst($item);
    $guide = array_combine($aisles, $letters);
    $itemUC = UCfirst($item);
    $firstChar = $itemUC[0];
    $location = array_search($firstChar, $guide);
    echo "$itemUC is located on Aisle $location.";
}           

//run function
checkAisle("banana");

Answer 1

我要原谅你在你的功能中使用$term但$item这一事实（这可能是你尝试自我解决的结果，所以为了方便起见，我假设这是固定的... ...你的代码在array_combine()行开始变坏了。如果你打电话：

var_export($guide);

你会看到：

array (
  1 => 'M',
  2 => 'Z',
)

这是因为您的键数组和值数组参数相反，结果是每个后续值和预先存在的键都会覆盖该值（键必须是唯一的）。然后，如果您尝试查找任何不在$guide中作为值存在的字母，您将收到false（布尔值，而不是字符串 - 它作为零长度字符串回显） array_search()。因此，您的功能仅适用于以M或Z开头的字符串。

无论如何，这是错误的。如果你想改进你的代码......

您只需要隔离并大写第一个字母，然后将该字符与大写字母M进行比较。

代码：（Demo）

function checkAisle($term) {
    $location = ($itemUC = strtoupper($term[0])) < "M" ? 1 : 2;
    return "$itemUC is located on Aisle $location.";
}           

echo checkAisle("banana") , "\n";
echo checkAisle("guava") , "\n";
echo checkAisle("lemon") , "\n";
echo checkAisle("melon") , "\n";
echo checkAisle("nectarine") , "\n";
echo checkAisle("Trump");

输出：

B is located on Aisle 1.
G is located on Aisle 1.
L is located on Aisle 1.
M is located on Aisle 2.
N is located on Aisle 2.
T is located on Aisle 2.

这是另一个版本，它包含一个生成的查找数组，并检查第一个字符实际上是一个字母：

代码：（Demo）

function checkAisle($term) {
    if (!ctype_alpha($term[0])) {
        return "First character out of bounds";
    }
    $locations = array_fill_keys(range('A','L'),1)+array_fill_keys(range('M','Z'),2);
    $letter = strtoupper($term[0]);
    return "$letter is located on Aisle {$locations[$letter]}.";
}    

echo checkAisle("Trump") , "\n";
echo checkAisle("banana") , "\n";
echo checkAisle("melon") , "\n";
echo checkAisle("guava") , "\n";
echo checkAisle("nectarine") , "\n";
echo checkAisle("lemon") , "\n";

Answer 2

因为您将$aisles数组指定为组合数组键并将$letters指定为值，而您无法将其指定为切换它，然后只需按键/字母选择数组即可返回过道。

<?php
//create function to compare first letter of item to the aisle arrays
function checkAisle($item) {
    $letters = range('A', 'Z');
    $aisles = array("1", "1", "1", "1", "1", "1", "1","1", "1", "1", "1", "1", "1", "2", "2", "2", "2", "2", "2", "2","2", "2", "2", "2", "2", "2");
    $guide = array_combine($letters, $aisles);
    $itemUC = ucfirst($item);
    $firstChar = $itemUC[0];
    echo "$itemUC is located on Aisle $guide[$firstChar].";
}           

//run function
checkAisle("banana");

https://3v4l.org/SddjA

<强>结果：

Banana is located on Aisle 1.

或者更好的方式（处理错误），假设您可能想要为硬编码阵列添加更多通道，或者字母A实际上位于过道2而不是1。

<?php
//create function to compare first letter of item to the aisle arrays
function checkAisle($item = null) {
    // check param
    if (empty($item) || is_numeric($item)) {
        throw new InvalidArgumentException('Error: function checkAisle is expecting string');
    }

    // build data
    $letters = range('A', 'Z');
    $aisles = [
        "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", "1", 
        "2", "2", "2", "2", "2", "2", "2", "2", "2", "2", "2", "2", "2"
    ];
    $guide = array_combine($letters, $aisles);

    // 
    $itemUC = ucfirst($item);
    $firstChar = isset($itemUC[0]) ? $itemUC[0] : null;

    if (!isset($guide[$firstChar])) {
        return 'Item '.$itemUC.' not found in store.';
    }

    return $itemUC.' is located on Aisle '.$guide[$firstChar];
}           

//run function
try {
    echo checkAisle("banana").PHP_EOL;
    echo checkAisle("twix").PHP_EOL;
    echo checkAisle("-").PHP_EOL;

    echo checkAisle(123).PHP_EOL;
} catch (InvalidArgumentException $e) {
    echo $e->getMessage();
}

Answer 3

<?php
//create function to compare first letter of item to the aisle arrays
function checkAisle($term) {
    $item= "banana";
    $letters = array("A", "B", "C", "D", "E", "F", "G","H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T","U", "V", "W", "X", "Y", "Z");
    $aisles = array("1", "1", "1", "1", "1", "1", "1","1", "1", "1", "1", "1", "1", "2", "2", "2", "2", "2", "2", "2","2", "2", "2", "2", "2", "2");
    $itemUC = UCfirst($item);
    $guide = array_combine($letters, $aisles);
    $itemUC = UCfirst($item);
    $firstChar = $itemUC[0];



    $location = $guide[$firstChar];


    echo "$itemUC is located on Aisle $location.";
}           

//run function
checkAisle("banana");

使用array_combine，你重复使用密钥1，它会覆盖所有其他密钥。

Answer 4

嗯，这是我的解决方案。当没有找到有效的字母时，它将返回0。您可以轻松添加多个过道。

  function checkAisle($name) {

   $letter = strtolower($name[0]);
   $result = 0; 

   if(in_array($letter, range('a', 'm'))){
    $result = 1; 
   }

   if(in_array($letter, range('n', 'z'))){
    $result = 2; 
   }

   // aisle 3, 4, 5, ... here

   return $result;

  }

从array_search显示密钥

4 个答案: