PHP check value against multiple values with OR-operator

Question

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 = '';
}

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

First debug by checking what the value of $ext is being set to — Chaim, May 01 '16 at 20:55
I just rechecked and $ext is being set correctly for each file (example.php returns "php") — mcky, May 01 '16 at 20:59
(('txt')||('rtf')||('log')||('docx')) will always evaluate to 1 and only then be compared to $ext — Chaim, May 01 '16 at 20:59
Your initial `if` will always return true, hence why you're always getting `test-` back. — mferly, May 01 '16 at 21:00
Solutions don't belong in questions. For that we have answers. — Rizier123, May 01 '16 at 21:18

score 22 · Accepted Answer · edited May 01 '16 at 21:41

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.

If statement:

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

Comes down to:

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

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

Multiple comparison

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()`

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))

_{Note: Second parameter is for strict comparison}

`switch()`

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;

}

Please tell me we have a good duplicate for this :)? Otherwise we just create it right here right now. — Rizier123, May 01 '16 at 21:00
That works great, Thanks for the help showing how to do it the right way — mcky, May 01 '16 at 21:08

score 2 · Answer 2 · answered May 01 '16 at 21:05

I would simply change it to something like this:

//This gets the extention for the file and assigns the class to the icon <i>
$pieces = explode('.', $fname);
$ext = array_pop($pieces);
if(in_array($ext,array('txt','rtf','log','docx'))){
    $pClass = 'text-';
}elseif(in_array($ext,array('zip','sitx','7z','rar','gz'))){
    $pClass = 'archive-';
}elseif(in_array($ext,array('php','css','html','c','cs','java','js','xml','htm','asp'))) {
    $pClass = 'code-';
}elseif(in_array($ext,array('png','bmp','dds','gif','jpg','psd','pspimage','tga','svg'))){
    $pClass = 'image-';
}else {
    $pClass = '';
}

score 1 · Answer 3 · answered May 01 '16 at 21:04

1

You can use in_array() to compare a value to multiple strings:

if(in_array($ext, array('txt','rtf','log','docx')){
    // Value is found.
}

answered May 01 '16 at 21:04

Chaim

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PHP check value against multiple values with OR-operator

3 Answers3

Multiple comparison

`in_array()`

`switch()`

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