Any easy way to eliminate everything but alphanumeric values from a variable/array?

[marcnyc]

I have a variable that will become the name of a file on hard drive/server so I need to eliminate EVERYTHING from the variable except for alphabetical & numerical values and characters allowed in file names (such as dash -, underscore _ etc)...

I have looked in the manual and I found this:

$search = array ("'<script[^>]*?>.*?</script>'si",  // Strip out javascript
                "'<[\/\!]*?[^<>]*?>'si",            // Strip out html tags
                "'([\r\n])[\s]+'",                  // Strip out white space
		"' '",				    // Strip out white space
                "'&(quot|#34);'i",                  // Replace html entities
                "'&(amp|#38);'i",
                "'&(lt|#60);'i",
                "'&(gt|#62);'i",
                "'&(nbsp|#160);'i",
                "'&(iexcl|#161);'i",
                "'&(cent|#162);'i",
                "'&(pound|#163);'i",
                "'&(copy|#169);'i",
                "'&#(\d+);'e");                     // evaluate as php

$replace = array ("",
                 "",
                 "\\1",
		 "",
                 "\"",
                 "&",
                 "<",
                 ">",
                 " ",
                 chr(161),
                 chr(162),
                 chr(163),
                 chr(169),
                 "chr(\\1)");

$name_file = preg_replace ($search, $replace, $name_artist);

I think I could use this function if I manually added ALL the symbols that are not allowed to the $search array but I was thinking that there must be an easier way, a specific function that eliminates everything except alphanumeric files. Isn't there?

I looked on the manual but did not find anything... I found rawurlencode() that does exactly what I need (replaces all non-alphanumerical values except for _ and - and .) but in rawurlencode() it replaces it with hex ditigs... I need to replace it with, say, underscores...

Also, since I am asking about this function, can somebody tell me what the "i", the "si" and the "+" stand for in the above function... Out of curiosity... I have looked on the manual but couldn't find that information...

Thanks and sorry for asking so many questions...

[Wave]

<?php

function specific_function ($name, $replacement="_"){
	return eregi_replace("[^a-zA-Z0-9_\\-\\.]{1}", $replacement, $name);
}

echo specific_function ("ghr%^&$001.txt");

?>

this echoed "ghr____001.txt"

^ means "not"

so you can just list ALLOWED symbols and replase this symbols with underscores i.e.

don't hesistate to ask, if you still need any help.

regards

[marcnyc]

That worked for me, thank you, except that the \ slash was not eliminated so I added:

stripslashes(specific_function($file));

by the way...
where can I find some beginner's tutorial on PHP to learn how to interpret this?

For example what do the ^ \ and {1} symbols represent in your function?

Also I had asked what i, + and si stand for in the first function I posted.... I was just wondering if you can enlighten me for general knowledge...

I did solve my problem though, so thank you very much

[marcnyc]

actually I still have a problem... when I added stripslashes I realized it does only remove backslashes but not forward slashes, how can I remove those?

after I called my function alphanumeric() I did this:

$name_file = str_replace('\\', '-',stripslashes(alphanumeric($name_file)));

and it looks like it workes...

BY THE WAY: for some reason it looks like this forum does not print the \ slash sign. I put two of those in the middle of the function... I'll try pasting it here in plain text:

$name_file = str_replace('\', '-',stripslashes(alphanumeric($name_file)));

if it's wrong or if there is any more specific function let me know so I learn