PHP使用OR运算符检查多个值的值 [英] PHP check value against multiple values with OR-operator

问题描述

我有一个文件名（ $ fname ），我需要将 $ pClass 分配给文件类型 - 之后。目前我总是得到 text - ，无论它是什么文件类型。

I have a filename($fname) and I need to assign $pClass to the file type with a "-" afterwards. Currently I always get text-, no matter what file type it is.

//This gets the extention for the file and assigns the class to the icon <i>
$pieces = explode('.', $fname);
$ext = array_pop($pieces);

if($ext == (('txt')||('rtf')||('log')||('docx'))){
  $pClass = 'text-';
}
else if($ext == (('zip')||('sitx')||('7z')||('rar')||('gz'))){
  $pClass = 'archive-';
}
else if($ext == (('php')||('css')||('html')||('c')||('cs')||('java')||('js')||('xml')||('htm')||('asp'))){
  $pClass = 'code-';
}
else if($ext == (('png')||('bmp')||('dds')||('gif')||('jpg')||('psd')||('pspimage')||('tga')||('svg'))){
  $pClass = 'image-';
}
else {
  $pClass = '';
}

为什么带有OR运算符的if语句不起作用？

Why doesn't my if statement with the OR operator works?

推荐答案

逻辑 || （OR）运算符无法正常工作。 || 运算符始终计算为布尔值TRUE或FALSE。因此，在您的示例中，您的字符串将转换为布尔值然后进行比较。

The logical ||(OR) operator doesn't work as you expect it to work. The || operator always evaluates to a boolean either TRUE or FALSE. So in your example your strings get converted into booleans and then compared.

如果声明：

if($ext == ('txt' || 'rtf'|| 'log' || 'docx'))

归结为：

if($ext == (TRUE || TRUE || TRUE || TRUE))
if($ext == TRUE)

---

要解决此问题并使代码按您的意愿运行，您可以使用不同的方法。

---

To solve this problem and get the code to work as you want it to you can use different methods.

解决问题并根据多个值检查值的一种方法是，实际将值与多个值进行比较：

One way to solve the problem and check your values against multiple values is, to actually compare the value against multiple values:

if($ext == "txt" || $ext == "rtf" /* || ... */)

in_array（）

另一种方法是使用函数 in_array （）并检查值是否为eq ual到其中一个数组值：

in_array()

Another way is to use the function in_array() and check if the value is equal to one of the array values:

if(in_array($ext, ["txt", "rtf" /* , ... */], TRUE))

_{注意：第二个参数用于严格比较}

您还可以使用开关根据多个值检查您的价值，然后让案件落空。

You could also use switch to check your value against multiple values and just let the case fall through.

switch($ext){

    case "txt":
    case "rtf":
 /* case ...: */
        $pClass = "text-";
    break;

}

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