PHP glob with case-insensitive matching

Question

I use glob for finding folders as

$str = "Test Folder";
$folder = glob("$dir/*$str*");

How can I tell glob to match to find the matching folders case-insensitive?

Matching test folder, TEST FOLDER, etc.

NOTE that $str is an unknown input to the script!

Answer 1

May I suggest the build of case-insensitive character ranges on each letter of $str?

Code: (Demo)

function glob_i($string){  // this function is not multi-byte ready.
    $result='';  // init the output string to allow concatenation
    for($i=0,$len=strlen($string); $i<$len; ++$i){  // loop each character
        if(ctype_alpha($string[$i])){  // check if it is a letter
            $result.='['.lcfirst($string[$i]).ucfirst($string[$i]).']';  // add 2-character pattern
        }else{
            $result.=$string[$i];  // add non-letter character
        }
    }
    return $result;  // return the prepared string
}
$dir='public_html';
$str='Test Folder';

echo glob_i($str);  // [tT][eE][sS][tT] [fF][oO][lL][dD][eE][rR]
echo "\n";
echo "$dir/*",glob_i($str),'*';  // public_html/*[tT][eE][sS][tT] [fF][oO][lL][dD][eE][rR]*

If you require a multibyte version, this is my suggested snippet: (Demo)

function glob_im($string,$encoding='utf8'){
    $result='';
    for($i=0,$len=mb_strlen($string); $i<$len; ++$i){
        $l=mb_strtolower(mb_substr($string,$i,1,$encoding));
        $u=mb_strtoupper(mb_substr($string,$i,1,$encoding));
        if($l!=$u){
            $result.="[{$l}{$u}]";
        }else{
            $result.=mb_substr($string,$i,1,$encoding);
        }
    }
    return $result;
}
$dir='public_html';
$str='testovací složku';

echo glob_im($str);  // [tT][eE][sS][tT][oO][vV][aA][cC][íÍ] [sS][lL][oO][žŽ][kK][uU]
echo "\n";
echo "$dir/*",glob_im($str),'*';  // public_html/*[tT][eE][sS][tT][oO][vV][aA][cC][íÍ] [sS][lL][oO][žŽ][kK][uU]*

Related Stackoverflow page:

Can PHP's glob() be made to find files in a case insensitive manner?

---

p.s. If you don't mind the expense of regex and/or you prefer a condensed one-liner, this will do the same: (Demo)

$dir='public_html';
$str='Test Folder';
echo "$dir/*",preg_replace_callback('/[a-z]/i',function($m){return '['.lcfirst($m[0]).ucfirst($m[0])."]";},$str),'*';  // $public_html/*[tT][eE][sS][tT] [fF][oO][lL][dD][eE][rR]*

and here is the multi-byte version: (Demo)

$encoding='utf8';
$dir='public_html';
$str='testovací složku';
echo "$dir/*",preg_replace_callback('/\pL/iu',function($m)use($encoding){return '['.mb_strtolower($m[0],$encoding).mb_strtoupper($m[0],$encoding)."]";},$str),'*';  // public_html/*[tT][eE][sS][tT][oO][vV][aA][cC][íÍ] [sS][lL][oO][žŽ][kK][uU]*